Conventional Prompt Global Strike and Long-Range · PDF fileThe Prompt Global Strike Mission (PGS) ... It is also funding research, through both DARPA and the Air Force, into hypersonic

Conventional Prompt Global Strike and

Long-Range Ballistic Missiles:

Background and Issues

Amy F. Woolf

Specialist in Nuclear Weapons Policy

April 6, 2018

Congressional Research Service

7-5700

www.crs.gov

R41464

Conventional Prompt Global Strike and Long-Range Ballistic Missiles


Summary Conventional prompt global strike (CPGS) weapons would allow the United States to strike

targets anywhere on Earth in as little as an hour. This capability may bolster U.S. efforts to deter

and defeat adversaries by allowing the United States to attack high-value targets or “fleeting

targets” at the start of or during a conflict. Congress has generally supported the PGS mission, but

it has restricted funding and suggested some changes in funding for specific programs.

CPGS weapons would not substitute for nuclear weapons, but would supplement U.S.

conventional capabilities. They would provide a “niche” capability, with a small number of

weapons directed against select, critical targets. Some analysts, however, have raised concerns

about the possibility that U.S. adversaries might misinterpret the launch of a missile with

conventional warheads and conclude that the missiles carry nuclear weapons. The U.S.

Department of Defense (DOD) is considering a number of systems that might provide the United

States with long-range strike capabilities.

The Air Force and Navy have both considered deploying conventional warheads on their long-

range ballistic missiles. The Air Force and the Defense Advanced Research Projects Agency

(DARPA) sought to develop a hypersonic glide delivery vehicle that could deploy on a modified

Peacekeeper land-based ballistic missile, but test failures led to the termination of this program.

In the mid-2000s, the Navy sought to deploy conventional warheads on a small number of Trident

II submarine-launched ballistic missiles, but Congress rejected the requested funding for this

program in 2008. Since then, the Pentagon has continued to develop a hypersonic glide vehicle,

now known as the Alternate Reentry System, which could be deployed on long-range missiles. At

present, it seems likely that this vehicle could be deployed on intermediate-range missiles on

Navy submarines, for what is now known as the Prompt Strike Mission. Congress may review

other weapons options for the CPGS mission, including bombers, cruise missiles, and possibly

scramjets or other advanced technologies.

The Pentagon’s budget request for FY2019 increases funding for the CPGS program from around

$201 million in FY2018 to $278 million in FY2019; it also shows significant increases in funding

over the next five years, with a total of $1.9 billion allocated to the program. This shows the

growing priority placed on the program in the Pentagon and the growing interest in Congress in

moving the program forward toward deployment.

When Congress reviews the budget requests for CPGS weapons, it may question DOD’s rationale

for the mission, reviewing whether the United States might have to attack targets promptly at the

start of or during a conflict, when it could not rely on forward-based land or naval forces. It might

also review whether this capability would reduce U.S. reliance on nuclear weapons or whether, as

some critics have asserted, it might upset stability and possibly increase the risk of a nuclear

response to a U.S. attack. This risk derives, in part, from the possibility that nations detecting the

launch of a U.S. PGS weapon would not be able to determine whether the weapon carried a

nuclear or conventional warhead. Congress has raised concerns about this possibility in the past.

Warheads deployed on boost-glide systems would not be affected by the 2010 New START

Treaty because these are new types of strategic offensive arms. But those deployed in existing

types of reentry vehicles on existing types of ballistic missiles would count against the treaty

limits. This report will be updated as needed.



Contents

Introduction ..................................................................................................................................... 1

Background ..................................................................................................................................... 2

The Prompt Global Strike Mission (PGS)................................................................................. 2 Rationale for the PGS Mission ........................................................................................... 2 PGS and the U.S. Strategic Command ................................................................................ 5 Potential Targets for the PGS Mission ................................................................................ 5

Conventional Ballistic Missiles and the PGS Mission .............................................................. 6

Plans and Programs ......................................................................................................................... 9

Air Force Programs ................................................................................................................... 9 The FALCON Study ........................................................................................................... 9 Reentry Vehicle Research and Warhead Options ............................................................... 11 Missile Options .................................................................................................................. 11 The Conventional Strike Missile ...................................................................................... 12 Hypersonic Test Vehicle (HTV-2) .................................................................................... 13 ArcLight ............................................................................................................................ 15

Army Advanced Hypersonic Weapon ..................................................................................... 15 Navy Programs ........................................................................................................................ 16

Reentry Vehicle Research ................................................................................................. 16 Conventional Trident Modification ................................................................................... 18 Submarine-Launched Intermediate-Range Global Strike ................................................. 19

Legislative Activity ................................................................................................................. 21 FY2003 and FY2004......................................................................................................... 21 FY2005 ............................................................................................................................. 22 FY2006 and FY2007......................................................................................................... 22 FY2008 ............................................................................................................................. 24 FY2009 ............................................................................................................................. 25 FY2010 ............................................................................................................................. 26 FY2011 ............................................................................................................................. 26 FY2012 ............................................................................................................................. 27 FY2013 ............................................................................................................................. 28 FY2014 ............................................................................................................................. 28 FY2015 ............................................................................................................................. 29 FY2016 ............................................................................................................................. 29 FY2017 ............................................................................................................................. 30 FY2018 ............................................................................................................................. 31 FY2019 ............................................................................................................................. 31

Issues for Congress ........................................................................................................................ 32

Assessing the Rationale for CPGS .......................................................................................... 32 Reducing Reliance on Nuclear Weapons .......................................................................... 32 PGS ................................................................................................................................... 33

The Potential for Misunderstanding a CPGS Missile Launch ................................................ 34 Mitigating the Risks .......................................................................................................... 35 Remaining Concerns ......................................................................................................... 36

Reviewing the Alternatives ..................................................................................................... 37 Land-Based Ballistic Missiles ........................................................................................... 37 Submarine-Launched Ballistic Missiles............................................................................ 38



Long-Range Bombers ....................................................................................................... 38 Tomahawk Cruise Missiles ............................................................................................... 39 Hypersonic Cruise Missiles .............................................................................................. 39 Scramjet Technologies ...................................................................................................... 39 Forward-Based Global Strike (FBGS) .............................................................................. 40

Arms Control Issues ................................................................................................................ 40 Potential Threats from Hypersonic Strike ............................................................................... 42 Weighing the Benefits and Risks ............................................................................................ 43

Contacts

Author Contact Information .......................................................................................................... 45

Acknowledgments ......................................................................................................................... 45


Congressional Research Service 1

Introduction Members of Congress and Pentagon officials have placed a growing emphasis on U.S. programs

to develop hypersonic weapons as a part of an effort to acquire the capability for the United

States to launch attacks against targets around the world in under an hour. Hypersonic weapons

can travel faster than Mach 5, or about 1 mile to 5 miles per second.1 This interest is driven by

both the perceived mission need for conventional prompt strike systems and concerns about

falling behind Russia and China in the development of these technologies.2 The United States is

pursuing two key technologies for this purpose: boost-glide systems that place a hypersonic glider

atop a ballistic missile booster and hypersonic cruise missiles that would use scramjet

technologies.

This report focuses, primarily, on the Pentagon’s ongoing program to develop ballistic missile-

based conventional prompt strike systems. This effort has been underway for about 15 years. The

George W. Bush Administration demonstrated an interest in the use of conventional weapons for

precision, long-range strike missions in the 2001 Nuclear Posture Review (NPR). This study

called for the integration of precision conventional weapons with strategic nuclear forces in a new

category of “offensive strike” weapons.3 Several other Pentagon studies published during the

Bush Administration also called on the United States to develop the capability to attack targets

around the world, in under an hour, with conventional warheads.

The Obama Administration, in the 2010 NPR, also emphasized the role that long-range, non-

nuclear systems could play in supporting “U.S. regional deterrence and reassurance goals.” The

2010 NPR indicated that conventional power projection capabilities were part of “effective

regional security architectures,”4 arguing that these capabilities could help the United States

assure and defend its allies, while reducing the role of nuclear weapons in U.S. security strategy.

The Trump Administration’s Nuclear Posture Review did not address the role of advanced

conventional weapons in U.S. nuclear posture, but the Administration has shown continuing

support for the development of long-range precision conventional weapons in its budget request

for FY2019. In addition, the Administration’s missile defense review may address growing

concerns about the U.S. ability to defend against hypersonic weapons under development by

Russia and China.

In 2003, the Department of Defense (DOD) specifically identified a new mission—prompt global

strike (PGS)—that sought to provide the United States with the ability to strike targets anywhere

on Earth with conventional weapons in as little as an hour, without relying on forward based

forces. DOD argued that this capability would bolster U.S. efforts to deter and defeat adversaries

by providing the United States with the ability to attack high-value targets or “fleeting targets”

that might be visible for only a short amount of time promptly, at the start of or during a conflict.

DOD has considered a number of systems that might provide the United States with long-range

1 Jason L. Sherman, “The Hypersonic Arms Race Heats Up,” The Daily Beast, December 3, 2017,

https://www.thedailybeast.com/the-hypersonic-arms-race-heats-up. See, also, Paul McCleary, “China Loves DoD

Acquisition Culture, Says R&D Chief Griffin,” Breaking Defense, March 6, 2018, https://breakingdefense.com/2018/

03/china-loves-dod-acquisition-culture-says-r/. 2 “HASC Seapower Chair Wittman Presses For Hypersonic Focus,” Breaking Defense, February 22, 2018,

https://breakingdefense.com/2018/02/hasc-seapower-chair-wittman-presses-for-hypersonic-focus/. 3 U.S. Congress, Senate Committee on Armed Services, Hearing on the Nuclear Posture Review, Statement of the

Honorable Douglas J. Feith, Under Secretary of Defense for Policy, February 14, 2002, p. 4. 4 U.S. Department of Defense, Nuclear Posture Review, Washington, DC, April 6, 2010, p. 34,

http://www.defense.gov/npr/docs/2010%20Nuclear%20Posture%20Review%20Report.pdf.



strike capabilities. These include bombers, cruise missiles, ballistic missiles, and boost-glide

technologies that would mate a rocket booster with a hypersonic glide vehicle.

During the George W. Bush Administration, analysts began to note that long-range ballistic

missiles armed with conventional warheads would be an ideal weapon for this mission. They

argued that these weapons, based in the United States or on submarines at sea, could attack

targets worldwide with a high degree of precision in a short amount of time. However, during the

latter years of the Bush Administration and the early years of the Obama Administration, DOD’s

programs began to focus on hypersonic weapons as the technology of choice for this mission. In

addition, in 2012, the Pentagon changed the focus of the program from “prompt global strike” to

“prompt strike,” which allowed the program to consider the deployment of a hypersonic glider on

a sea-based intermediate-range missile. The Pentagon is also conducting research, through

DARPA and the Air Force, into shorter-range, air-delivered, hypersonic cruise missiles.

Some analysts have questioned the need for these programs, raising concerns, for example, about

the possibility that U.S. adversaries might misinterpret the launch of a missile with conventional

warheads and conclude that the missiles carry nuclear weapons. They have also questioned

whether existing U.S. military capabilities might meet the need for prompt, conventional attacks

in most potential conflict scenarios without raising the risk of miscalculation or

misunderstanding. Congress has generally supported the rationale for the prompt strike mission.

In the past, it has restricted funding and suggested changes in the direction of specific programs,

but, recently, it has pressed the Pentagon to place a higher priority on the program and to

accelerate its development. Congress is likely to continue to review the technologies and

programs related to this mission as a part of the annual authorization and appropriations process.

This report provides an overview of the rationale for the PGS/prompt strike mission and the

possible deployment of conventional warheads on long-range ballistic missiles or boost-glide

systems in support of this mission. It then reviews the Air Force and Navy efforts to develop these

systems. It summarizes congressional reaction to these proposals, and provides a more detailed

account of the issues raised by these concepts and programs.

Background

The Prompt Global Strike Mission (PGS)

Rationale for the PGS Mission

Throughout the Cold War, the United States maintained military bases overseas so that it could

position its troops to deter, and if necessary, respond promptly to an attack from the Soviet Union

or its allies. These forward bases were located, for the most part, in Europe and Asia—regions

where conflict seemed most likely to occur. These overseas bases and forces were believed not

only to increase preparedness, but also to deter conflict by their very presence in unstable regions.

However, with the demise of the Soviet Union and the end of the Cold War, analysts argued that

the United States must be prepared to fight in unexpected areas against a wide range of potential

adversaries who may possess a great variety of military capabilities. Although the United States

continues to deploy its military forces at bases around the world, it has begun to restructure, and,

in many cases, reduce, its forces based overseas. It has also sought to improve its ability to move

military forces into a region quickly when and if a conflict occurs. Moreover, as some observers

have noted, the United States can no longer be certain that these bases are located close to the

most likely areas of conflict.



As a result, many analysts and military officials have argued that the United States must maintain

and enhance its long-range strike capability so that it can strike anywhere in the world with forces

that are based in or near the United States,5 or with forces that have the range to reach targets

across the globe from wherever they are deployed. This would not only allow the United States to

pursue an adversary without relying on forward bases, it would also allow the United States to

reach targets deep inside an enemy’s territory if that area were out of the range of U.S. forces

deployed at bases or on naval forces in the region. Moreover, if an adversary developed air

defenses or other capabilities that could deny U.S. aircraft access to critical targets, a long-range

strike capability based on ballistic missile technologies could prove valuable if launched early, as

a “leading-edge” capability that degraded an opponent’s defenses. Analysts argue that these types

of systems would be far less sensitive to an adversary’s anti-access and area denial (A2/AD)

efforts.

Further, some analysts argue that the United States must be able to attack targets across the globe

in a matter of hours or less, either at the start of a conflict or during ongoing operations. This is

because U.S. adversaries might adapt to the U.S. precision-strike capability by denying targeting

information with concealment techniques or mobility, leaving the United States with little time to

attack after it identified relevant targets. Moreover, many have noted that adversaries could seek

to protect their assets by deploying them in buried or hardened facilities, leading to a requirement

for improvements in the U.S. ability to defeat hardened and deeply buried targets promptly,

before the adversary employed the hidden capabilities.

The need for prompt long-range, or global, strike capabilities has been addressed in general

defense policy studies, such as the 2001, 2006, and 2010 Quadrennial Defense Review (QDR)

Reports. The 2001 QDR noted that the U.S. defense strategy “rests on the assumption that U.S.

forces have the ability to project power worldwide.”6 The 2006 QDR expanded on the need for

prompt global strike capabilities, noting that they would provide the United States with the ability

“to attack fixed, hard and deeply buried, mobile and relocatable targets with improved accuracy

anywhere in the world promptly upon the President’s order.” This QDR went on to call for the

deployment of a prompt global strike capability, using Trident submarine-based ballistic missiles

armed with conventional warheads, within two to four years.7 The 2010 QDR also noted that

“enhanced long-range strike capabilities are one means of countering growing threats to forward-

deployed forces and bases and ensuring U.S. power projection capabilities.” It noted that DOD is

pursuing a number of programs to meet this need, and, as a part of this effort, “plans to

experiment with conventional prompt global strike prototypes.”8

DOD also addressed the prompt global strike mission in specific reports on Air Force doctrine,

which have noted that “rapid power projection based in the continental United States has become

the predominant military strategy.” In May 2003, the Air Force issued a formal Mission Need

Statement for the Prompt Global Strike (PGS) Mission. This statement indicated that the United

States should be able to strike globally and rapidly with joint conventional forces against high-

payoff targets, that the United States should be able to plan and execute these attacks in a matter

5 See, for example, Watts, Barry D., Long-Range Strike: Imperatives, Urgency, and Options. Center for Strategic and

Budgetary Assessments. April 2005. 6 U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, September 29, 2001, p. 43,

http://www.comw.org/qdr/qdr2001.pdf. 7 U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, February 6, 2006, pp. 49-50,

http://www.globalsecurity.org/military/library/policy/dod/qdr-2006-report.pdf. 8 U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, February 2010, pp. 32-33,

http://www.defense.gov/qdr/images/QDR_as_of_12Feb10_1000.pdf.



of minutes or hours—as opposed to the days or weeks needed for planning and execution with

existing forces—and that it should be able to execute these attacks even when it had no

permanent military presence in the region where the conflict would occur.9

Officials in the George W. Bush Administration viewed the prompt global strike mission as a

means to extend the U.S. capability to address global contingencies that could threaten U.S.

security and U.S. interests. For example, Admiral James O. Ellis, the commander of U.S.

Strategic Command (STRATCOM) from 2002 to 2004, explained that PGS would “provide a

wider range of options to the President in responding to time-critical global challenges.”10

General James Cartwright, who served as commander of STRATCOM between 2004 and 2007,

defined the global strike mission by stating that “it provides to the nation the ability to rapidly

plan and rapidly deliver effect any place on the globe.” The capability would not necessarily be

nuclear, and a regional combatant commander could “tailor it for his target and deliver it very

quickly, with very short time lines on the planning and delivery, any place on the face of the

Earth.”

General Cartwright also emphasized that the global strike capability involved much more than

just the delivery of a weapon to a target, stating that “it encompasses both the ability to plan

rapidly, to apply the precision to the intelligence and gather that intelligence in a very rapid

manner, and then to apply that intelligence to the target and understand the effect we want to

create.”11

The intelligence requirements for the PGS mission could, however, prove quite

demanding. General Michael Hayden, then the CIA director, noted in mid-2007 that the PGS

mission will require “very convincing intelligence” before any attacks occur.12

He stated “If you

are going to strike suddenly ... it has to be based on very powerful, very convincing intelligence.”

In addition, the intelligence may need to be released to the public, to demonstrate both the

military need and time restraints that made the attack necessary. Moreover, most analysts agree

that the United States does not yet have the capability to meet the intelligence demands of the

PGS mission.

The Obama Administration’s description of the prompt global strike mission focused more on

regional than global challenges. As was noted above, the 2010 QDR described the PGS mission

as one possible means to address “growing threats to forward-deployed forces and bases and

ensuring U.S. power projection capabilities.” The 2010 Nuclear Posture Review similarly viewed

PGS as an important component of U.S. regional deterrence capabilities when it noted that “these

capabilities may be particularly valuable for the defeat of time-urgent regional threats.”13

This

change in focus was reflected in Pentagon guidance in 2012; the program was then known as

Conventional Prompt Strike (CPS), rather than Conventional Prompt Global Strike (CPGS).

The Trump Administration did not address either a prompt global strike or prompt strike mission

in its National Defense Strategy or its Nuclear Posture Review. However, it has continued to

9 This document was written by Air Force Space Command, coordinated with officials in the Joint Staff and the Office

of the Secretary of Defense, and validated by the Joint Requirements Oversight Council (JROC). See, General John

Jumper, U.S. Air Force, Final Mission Need Statement. “Prompt Global Strike,” May 2, 2003. 10 Statement of Admiral James O. Ellis, Commander, U.S. Strategic Command, House Armed Services Committee,

March 13, 2003. 11 U.S. Congress, Senate Committee on Armed Services, Subcommittee on Strategic, Testimony of Admiral James E.

Cartwright, Commander, U.S. Strategic Command, Hearing, April 4, 2005. 12 Grossman, Elaine, M., “Hayden: ‘Prompt Global Strike’ Raises Bar for Intel Community.” Inside The Air Force.

June 22, 2007. 13 U.S. Department of Defense, Nuclear Posture Review, Washington, DC, April 6, 2010, p. 34,

http://www.defense.gov/npr/docs/2010%20Nuclear%20Posture%20Review%20Report.pdf.



support funding for hypersonic technologies in its FY2019 defense budget request. In addition,

Michael Griffen, the Pentagon’s Undersecretary for Research and Engineering, has emphasized

that the Pentagon does intend to place a high priority on pursuing U.S. prompt strike programs.14

PGS and the U.S. Strategic Command

In October 2002, STRATCOM, which was in charge of plans and operations for U.S. strategic

nuclear weapons, merged with U.S. Space Command (SpaceCom), which commanded military

space operations, information operations, computer network operations, and space campaign

planning.15

This merger gave the new STRATCOM the “ability to project power around the globe

through space and information warfare.” Further, in late 2002 and early 2003, the Pentagon

restructured the new STRATCOM so that it could take on new missions, including the planning

and execution of the prompt global strike mission.16

This change in the command structure

highlighted the growing emphasis on long-range, strategic missions in conventional warfighting

doctrine.

In July 2006, STRATCOM established its joint functional component command for global strike

(JFCC-GS). According to its mission statement, JFCC-GS “is designed to optimize planning,

execution and force management for the assigned missions of deterring attacks against the United

States, its territories, possessions and bases.” Among other tasks, it “provides integrated global

strike capabilities to deter and dissuade threats and when directed, defeat adversaries through

decisive joint global kinetic and non-kinetic combat effects.”17

Potential Targets for the PGS Mission

Analysts have identified a number of potential targets that the United States might need to strike

promptly, either at the start of or during a conflict with a regional adversary.18

For example, if an

adversary deployed air defense or anti-satellite weapons that could disrupt the U.S. ability to

sustain an attack, the United States might choose to strike promptly at the start of a conflict with

weapons that could penetrate and destroy the defenses. A prompt strike against an adversary’s

ballistic missiles or caches of weapons of mass destruction (WMD) might allow the United States

to destroy these weapons before an adversary could use them. The United States might also use

prompt, long-range weapons to attack an adversary’s command and control capabilities, to

degrade or undermine its operations early in a conflict.

The United States might also be faced with circumstances during an ongoing conflict when it

would need to destroy targets that could appear quickly and remain vulnerable for short periods

of time. These might include leadership cells that could move during a conflict or mobile military

14 Paul McCleary, “China Loves DoD Acquisition Culture, Says R&D Chief Griffin,” Breaking Defense, March 6,

2018, https://breakingdefense.com/2018/03/china-loves-dod-acquisition-culture-says-r/. 15 U.S. Department of Defense, “DOD Announces Merger of U.S. Space and Strategic Commands,” June 26, 2002. 16 According to Admiral James O. Ellis, the Commander of STRATCOM, these missions included global strike

planning and execution; information operations; global missile defense integrations; and oversight of command,

control, communications, computers, intelligence, surveillance, and reconnaissance (C4ISR) in support of strategic and

global operations. See Statement of Admiral James O. Ellis, Commander United States Strategic Command, before the

House Armed Services Committee, March 13, 2003, p. 4.

17 http://www.stratcom.mil/factsheets/gs/.

18 A description of some of these scenarios can be found in the National Academies Study on Prompt Global Strike.

See Committee on Conventional Prompt Global Strike Capability, National Research Council of the National

Academies, U.S. Conventional Prompt Global Strike: Issues for 2008 and Beyond, Washington, DC, 2008, pp. 31-33.



systems that the adversary had chosen to keep hidden prior to their use. These types of targets

might only be vulnerable to weapons that the United States could launch promptly and direct to

their targets quickly. Analysts have noted that PGS might provide the means to attack such targets

if the United States did not have the necessary weapons located near the conflict.

The Defense Science Board outlined several of these potential scenarios in a March 2009 report

prepared by the Task Force on Time Critical Conventional Strike from Strategic Standoff. This

report “formulated five representative scenarios” that might require a “very rapid strike response

to a developing situation.”19

These scenarios included several cases.

A near-peer competitor had used its emerging counter-space capability to destroy

a U.S. satellite.

The United States wanted to destroy a package of special nuclear materials that a

terrorist organization had shipped to a neutral country.

A small package of weapons of mass destruction was located temporarily in a

rural area of a neutral country.

The leadership of a terrorist organization had gathered in a known location in a

neutral country.

A rogue state armed with a nuclear weapon was threatening to use that weapon

against a U.S. ally.

Each of these cases provided scenarios where the United States might want to attack promptly at

the start of, or during, a conflict with a regional adversary. However, as some analysts have noted,

long-range prompt strike weapons may not always prove the best solution in all circumstances.

Even if the weapon could arrive within a relatively short amount of time, the United States might

not have the intelligence needed to pinpoint the target, particularly if it were moving. Moreover,

an adversary might detect the launch of the weapon and move it before the weapon arrived. As a

result, in some cases, a weapon that could loiter in or near the area of the conflict, and strike

within minutes when the target became evident, may be better than a weapon that could launch

promptly but might take more than an hour to arrive.20

Conventional Ballistic Missiles and the PGS Mission

The Obama Administration noted, in the 2010 NPR, that the Pentagon “is studying the

appropriate mix of long-range strike capabilities, including heavy bombers as well as non-nuclear

prompt global strike, in follow-on analysis to the 2010 QDR and the NPR.” The United States

might use a number of different weapons systems for this purpose. In the near term, these could

include medium- or long-range aircraft, cruise missiles launched from bombers or submarines,

and ballistic missiles based at sea or on land in the United States.21

But conventional aircraft,

19 U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology and Logistics,

Time Critical Conventional Strike from Strategic Standoff, Report of the Defense Science Board Task Force,

Washington, DC, March 2009, p. 2, http://www.acq.osd.mil/dsb/reports/ADA498403.pdf. 20 For a description of a range of possible scenarios, and the different requirements for prompt response, see James M.

Acton, Silver Bullet? Asking the Right Questions About Prompt Global Strike (Washington, DC: Carnegie Endowment

for International Peace, 2013), pp. 9-29. 21 In his testimony in 2003, Admiral Ellis specifically mentioned two systems that could contribute to this mission,

Trident submarines reconfigured to carry Tomahawk cruise missiles with conventional warheads and the proposed

Common Aero Vehicle, which could be used to deploy conventional munitions on long-range ballistic missiles. See the

statement of Admiral James O. Ellis, Commander, U.S. Strategic Command, House Armed Services Committee, March

13, 2003. In the longer term, the Air Force and Navy are both exploring the use of ramjets, or scramjets, for long-range

(continued...)



even if they are based near the theater of operations, could take several hours, or more, to reach

their targets. Aircraft may also be vulnerable to enemy air defenses, particularly if they tried to

attack targets deep inside enemy territory. Similarly, aircraft or cruise missiles based at sea may

be too far from the theater of operations to strike critical targets in a timely manner.

As a result, many analysts have suggested that the United States should use long-range ballistic

missiles (ICBMs and SLBMs) for the prompt global strike mission.22

During the Cold War, these

long-range ballistic missiles provided the United States with the ability to threaten targets

throughout the Soviet Union, and, if necessary, in other nations, from the United States or from

submarines patrolling at sea. But these missiles have always carried nuclear warheads.23

To use

them for the conventional prompt global strike mission, the United States would have to deploy

these missiles with conventional warheads. The Bush Administration first raised the profile of

long-range, conventional strike missiles in the 2001 NPR, when it introduced the concept of the

“new triad.” This concept joined long-range nuclear-armed missiles with precision-strike

conventional weapons in a category called offensive strike weapons. The Bush Administration

argued that the availability of precision conventional weapons would, possibly, provide the

President with more options in a crisis, and, therefore, reduce the likelihood of the use of nuclear

weapons.

The Pentagon’s Defense Science Board (DSB), in a study published in early 2004, asserted that

land-based long-range ballistic missiles have “unique, time-critical characteristics” that include

“responsiveness, range, speed, precision, lethality, and freedom of maneuver.”24

With these

capabilities, they could attack targets anywhere in the world within an hour of their launch,

without relying on forward bases or supporting military capabilities, such as the tanker aircraft

needed to support long-range flights by bombers. They would not be at risk from air defenses,

and there would be no risk to flight crews. Further, if the warheads could maneuver to slow their

reentry and increase their angle of attack, they might be effective against some types of hardened

and deeply buried targets. The DSB study asserted that these weapons could provide “a reliable,

low-cost force on continuous alert with a high readiness rate and the capability to immediately

react under strict control of the National Command Authority.” In other words, the high levels of

reliability, readiness, and command and control that were needed as a part of the U.S. strategic

nuclear deterrent during the Cold War are also valuable characteristics for a long-range

conventional strike system in the post-Cold War era.

(...continued)

attack term. These hypersonic aircraft, which could fly at speeds of Mach 2-Mach 5, are still in the early stages of

development. They are envisioned to launch from air bases, like aircraft, but to travel at speeds that far exceed those of

U.S. aircraft and may approach the speeds of missiles. See, for example, Pincus, Walter, “Pentagon Has Far-reaching

Defense Spacecraft in Works,” Washington Post, March 16, 2005. p. 3. 22 See, for example, U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition,

Technology, and Logistics, Report of the Defense Science Board Task Force on Future Strategic Strike Forces.

February 2004. See, also, Eric A. Miller and Willis A. Stanley, The Future of Ballistic Missiles. National Institute for

Public Policy, October 2003. 23 When the Cold War ended in the early 1990s these missiles carried more than 8,000 nuclear warheads. The United

States has reduced its strategic forces, and currently has 2,000 warheads deployed on around 786 ICBMs and SLBMs.

U.S. Department of State, The Legacy of START and Related U.S. Policies, Washington, DC, July 16, 2009,

http://www.state.gov/t/vci/rls/126119.htm. See also, U.S. Department of State, START Aggregate Numbers of Strategic

Offensive Arms, Washington, DC, July 1, 2009. http://www.state.gov/t/vci/rls/130149.htm. 24 U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics,

Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-1.



In testimony before the Senate Armed Services Committee in April 2005, General James

Cartwright, then the commander of STRATCOM, linked PGS to the “new Triad” concept

advanced by the 2001 NPR. General Cartwright noted that “the New Triad concept will enable

more precisely tailored global strike operations”25

by allowing the United States to choose

conventional rather than nuclear weapons to attack some categories of targets. By replacing some

nuclear weapons with conventional weapons in the U.S. strategic war plan the United States

might be able to further reduce its reliance on, and, therefore, its number of deployed strategic

nuclear weapons.26

General Cartwright and others emphasized that the substitution of conventional warheads for

nuclear warheads in the U.S. war plan would require significant improvements in the accuracy of

U.S. long-range ballistic missiles. If missiles could deliver their payloads more precisely to their

targets, then, for some categories of targets, they may not need the explosive yield of a nuclear

weapon to destroy the target. Both the Navy and the Air Force have explored advanced guidance

and targeting technologies, such as the use of GPS (global positioning systems), to provide their

missiles with these improvements in accuracy. This effort had been underway for more than two

decades. After General Cartwright sought a study that would allow him to determine what

proportion of the targets in the U.S. war plan could be attacked with conventional weapons, an

industry analyst estimated that this proportion could be between 10% and 30% of the existing

targets.27

Subsequently, however, some analysts and military officials questioned whether the United States

should seek to substitute conventional warheads for nuclear warheads in the U.S. nuclear war

plan. They noted that conventional warheads might lack the deterrent capabilities of nuclear

warheads, even if they could damage many targets, because they lack the psychological effects

associated with nuclear weapons. According to General Kevin Chilton, the former commander of

STRATCOM, this would not be a weapon that “engenders fear, compared to the threat of a

nuclear strike.” Instead, General Chilton and other analysts viewed long-range ballistic missiles

armed with conventional warheads as a “niche” weapon that might be used to attack some critical

targets in scenarios that would not have otherwise called for the use of nuclear weapons.28

In other words, instead of substituting for nuclear weapons, a new prompt global strike capability

would expand the range of U.S. conventional options. For example, General Chilton noted, in

2008 testimony before the Strategic Forces Subcommittee of the House Armed Services

Committee, that this type of weapon could “provide an additional arrow in the quiver, if you will,

of the country to address emerging threats, that we might find a nuclear weapon application to be

self-deterring to address that threat.”29

Even without direct substitution, however, CPGS still

might reduce U.S. reliance on nuclear weapons, because, with more conventional options, a

President might be less likely to authorize the use of a nuclear weapon to attack a critical target.

25 U.S. Congress, Senate Committee on Armed Services, Subcommittee on Strategic, Testimony of Admiral James E.

Cartwright, Commander, U.S. Strategic Command, Hearing, April 4, 2005. 26 Grossman, Elaine M., “U.S. General: Precise Long-Range Missiles may Enable Big Nuclear Cuts,” Inside the

Pentagon, April 28, 2005. 27 Ibid. 28 Carlo Munoz, “Chilton: Conventional PGS Cannot Replace Nuclear Deterrent Role,” Inside the Air Force, January

22, 2010. 29 U.S. Congress, House Armed Services, Strategic Forces, United States Strategic Posture and the Fiscal Year 2009

Budget Request for Strategic Programs, Hearing, 110th Cong., 2nd sess., March 27, 2008.



The idea that long-range systems armed with conventional warheads could enhance deterrence

remained evident in the discussion about a potential CPGS capability during the Obama

Administration. In February 2012, James Miller, then the Under Secretary of Defense for Policy,

noted that programs like CPGS could help strengthen U.S. non-nuclear forces as a part of the U.S.

deterrent.30

But, as had been evident in other discussions at the time, he referred to these systems’

ability to enhance U.S. conventional capabilities rather than their ability to substitute directly for

nuclear weapons.

Plans and Programs Both the Air Force and the Navy have studied the possible deployment of conventional warheads

on their long-range ballistic missiles in the past. The Air Force briefly studied the penetration

capabilities of conventional ICBMs in the mid-1990s. In August 1995 it launched an ICBM

armed with a “pointy” front end (and no explosive warhead) against a granite slab that had

characteristics similar to reinforced concrete. Press reports indicate that the warhead entered the

target at a 90 degree angle and penetrated to a depth of 30 feet, which is greater than the depth of

penetration of any existing U.S. weapon.31

The Navy also sponsored studies in the 1990s that

sought to develop a non-nuclear penetrating warhead for the Trident SLBM. These studies also

focused on questions about whether a reentry vehicle from a ballistic missile could penetrate a

hardened target, using only its speed and angle of reentry, without a nuclear explosion. Both the

Navy and the Air Force recognized that, without a nuclear explosion, the reentry vehicle from a

ballistic missile would have to be far more accurate than those deployed in the 1990s (and still

deployed today) to attack and destroy a buried target.

During the George W. Bush Administration, the Air Force and the Navy both pursued programs

that would provide a prompt global strike capability. However, in FY2008, Congress eliminated

funding for the Navy and Air Force programs, creating, instead, a combined, defense-wide

Conventional Prompt Global Strike program (CPGS) that would pursue research and

development into technologies that might contribute to the PGS mission. The program was to

fund the design, development, and acquisition of guidance systems, boosters, mission planning

capabilities, mission enabling capabilities, reentry systems, and payload delivery vehicles

(PDVs).32

Details on funding for this account are described below.

Air Force Programs

The FALCON Study

In 2003, the Air Force and DARPA (the Defense Advanced Research Projects Agency) initiated a

program, known as FALCON (force application and launch from continental United States) that

was designed to develop both a launch vehicle similar to a ballistic missile and a hypersonic

reentry vehicle, known as the common aero vehicle (CAV) that, together, would provide the

United States with the ability to meet the requirements of the prompt global strike mission.

30 Elaine M. Grossman, “Conventional Arms No Substitute for Nuclear: Strategic Command Official,” February 29,

2012. 31 Grossman, Elaine M. “Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs,” Inside the Pentagon,

June 27, 2002, p. 1. 32 FY 2011 RDT&E Budget Item Justification, PE 0604165D8Z.



The FALCON study outlined many of the requirements that would become part of the framework

for the conventional prompt global strike mission. For example, it indicated that the proposed

CAV, when launched by a modified ICBM or other launch vehicle, should be able to travel at five

times the speed of sound (Mach 5) so that it could deliver a substantial payload from the

continental United States to anywhere on Earth in less than two hours.33

The study identified a

number of objectives for the CAV system that would allow it to achieve these goals. It stated that

the CAV and its delivery vehicle should achieve alert status, which would make it ready to

launch, in under 24 hours and should then be able to launch from this alert status in less than 2

hours, once it had received an execution order. The study indicated that CAV should then be able

to reach its target within one hour of its launch.34

These characteristics would provide it with the

capabilities needed to attack time-sensitive targets.35

To meet the “global” portion of the PGS mission, the study indicated that the CAV should not

only have the range to “strike throughout the depth of an adversary’s territory,” it should also

have a cross-range capability of 3,000 nautical miles. The cross-range measures the ability of the

CAV to maneuver and vary from a standard ballistic trajectory after its release from its launch

vehicle. This ability to maneuver would allow the CAV to adjust to new information so that it

could attack mobile targets, if timely and accurate information became available and was

communicated to the CAV during its flight. It would also provide the CAV with a high degree of

accuracy, allowing it to deliver its weapons within a planned 3 meters of the intended target. The

CAV would also have to be linked to “complete, timely intelligence, surveillance, and

reconnaissance information.”

To minimize the risk of ambiguity or misinterpretation, where a nation observing the launch

might conclude it was under nuclear attack, the Air Force planned to segregate the missiles armed

with conventional warheads and deploy them far from bases with nuclear warheads. The missiles

could be deployed “on mobile launchers or in semi-buried silos or berms on each coast, ready to

launch on short notice.”36

The two potential bases included Vandenberg Air Force Base on the

West Coast and Cape Canaveral on the East Coast.

Analysts have also identified a number of interrelated capabilities that the United States would

need to be able to deliver weapons to targets across the globe within hours of a decision to

launch. The United States would need the intelligence, surveillance, and reconnaissance (ISR)

capability that would allow it to identify a target precisely and quickly. It would also need the

command and control capability to review the targets, plan the attack, target the delivery vehicles,

and order the launch within a short amount of time. Finally, it would need the continuing

reconnaissance capability to verify that the intended target remained available and that the

weapon reached and destroyed that target. The requirements would exist for both land-based and

sea-based missiles.

33 DARPA, “FALCON (Force Application and Launch from CONUS Technology Demonstration Program,” Fact

Sheet, November 2003. See, also, Pincus, Walter, “Pentagon has Far-Reaching Defense Spacecraft in the works. Bush

Administration Looking to Space to Fight Threats,” Washington Post, March 16, 2005, p. 3. 34 Report to Congress on the “Concept of Operations” for the Common Aero Vehicle, Submitted in response to

Congressional Reporting Requirements, by Peter B. Teets, Under Secretary of the Air Force, February 24, 2004. p. 2. 35 This implies that the U.S. command and control system would have the capability to identify potential targets, plan

the mission, and prepare to launch the CAV within this time frame. These capabilities would be needed for the PGS

mission, regardless of the munitions package on the ballistic missile. 36 Air Force Space Command, Common Aero Vehicle White Paper.



Reentry Vehicle Research and Warhead Options

As was noted above, the Pentagon’s Defense Science Board (DSB), in a study published in early

2004, supported the idea of using long-range ballistic missiles for the prompt global strike

mission because these missiles would have the required “responsiveness, range, speed, precision,

lethality, and freedom of maneuver” to attack targets anywhere in the world within an hour of

their launch.37

Moreover, the study went on to note that existing U.S. land-based ballistic missiles

could be converted to carry conventional warheads. According to the DSB study, modified

Minuteman II missiles might each be able to carry a single warhead that weighed between 500

and 1,000 pounds; a modified Peacekeeper could possibly carry between 6,000 and 8,000 pounds

of payload, which would allow for multiple warheads or reentry vehicles.38

According to some

estimates, these missiles could even destroy some targets without an explosive warhead, using the

“sheer force of impact of a reentry vehicle moving at 14,000 feet per second.”39

According to the

DSB study, Peacekeeper missiles could also carry a single reentry body that had been modified to

improve accuracy by allowing for the maneuverability of the warhead, like the E2 warhead

described above.

In addition, as was noted above, the United States could use a hypersonic glide vehicle, like the

CAV under consideration in the Falcon Study, as the reentry body on a long-range ballistic

missile. According to the Falcon Study, the CAV would be an unpowered, maneuverable

hypersonic glide vehicle capable of carrying approximately 1,000 pounds in munitions or other

payload.40

This vehicle is a cone-shaped winged body that, after launch aboard a booster derived

from a ballistic missile, would fly within the atmosphere at hypersonic speeds and maneuver to its

target. As is noted below, DOD has funded this program through the defense-wide Conventional

Prompt Global Strike (CPGS) program since FY2008.

The Air Force considered two types of warheads for the CPGS mission.41

One of these would

contain kinetic energy projectiles, like the flechettes described above, that would be fused to

disperse over a wide area after release from the payload delivery vehicle. The delivery body could

also carry an explosive warhead to enhance its capability to penetrate and destroy hardened and

buried targets. These munitions could be delivered by a hypersonic glide vehicle should such a

system become operational. However, if the United States determined that it needed a

conventional PGS capability in the near term, before the boost-glide technology was ready for

deployment, these munitions might be deployed in existing reentry vehicles that follow a ballistic

trajectory to their targets, like those currently deployed on U.S. nuclear-armed missiles.

Missile Options

In 2004, the Air Force indicated that it could modify both Minuteman II missiles and Peacekeeper

(MX) missiles to carry conventional warheads. The Minuteman II missile was first deployed in

1965 and was retired in the early 1990s. The Air Force deployed 450 of these missiles. Each

carried a single nuclear warhead and had a range of over 7,000 miles. The Air Force has already

37U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics,

Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-1. 38 Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-3. 39 Eric Schmitt, “U.S. Considers Conventional Warheads on Nuclear Missiles,” New York Times, February 24, 2003. 40 In 2006, the Bush Administration redesignated the CAV as the hypersonic technology vehicle, in response to the

restrictions in the FY2005 Defense Appropriations Act. 41 Major Jason E. Seyer, USAF, “Adding the Conventional Strike Missile to the U.S.’s Deterrence Toolkit,” High

Frontier, February 2009, p. 32.



modified some of these missiles, using some as target vehicles in tests of missile defense

technologies and a few in a space-launch configuration. The Peacekeeper missile was first

deployed in 1986. The Air Force deployed 50 of these missiles; each carried 10 warheads and had

a range greater than 6,000 miles. The Air Force deactivated these missiles between 2002 and

2005. It has now begun to modify these missiles and plans to use them not only for the PGS

mission, but also to launch satellites.

The Air Force renamed the modified Minuteman and Peacekeeper missiles, referring to them as

Minotaur missiles. The Minotaur IV missile would use three stages from the Peacekeeper missile

and a new fourth stage developed by Orbital Sciences Corporation. The Minotaur IV missile

could serve as the boost vehicle for a land-based CPGS mission. When it began to consider the

use of these missiles for the PGS mission, the Air Force stated that the modifications could be

made at a relatively low cost and low level of technical risk because they would use the missiles’

existing rocket motors. The avionics and guidance systems could rely, primarily, on existing

technologies, with some modifications to allow the upper stages of the missiles and their reentry

vehicles to maneuver for improved accuracy. The Air Force also indicated that a modified

Peacekeeper missile would be able to carry much larger payloads than the Trident missile.42

The Air Force began an Analysis of Alternatives (AOA) study in 2006 to review technologies and

programs that could meet the requirements of the prompt global strike mission. Reports indicate

that the Navy and Air Force collaborated on the study, exchanging information on “service-

specific” platforms, and considering a range of alternative platforms, across service lines, for the

long-term PGS option.43

These include a long-range land-based option, a shorter-range forward

deployed land-based missile, a sea-based option, and an air-breathing option. The Air Force

completed this study in 2008.44

The Conventional Strike Missile

As the AOA drew to a close in 2008, the Air Force began to pursue the development of a system

known as the conventional strike missile (CSM). It initially expected this missile to serve as a

mid-term follow-on to the conventional Trident modification (CTM) program,45

but after

Congress refused to fund development of the CTM, the CSM became the earlier option for the

PGS mission. Reports indicate that General Kevin Chilton, then the commander of STRATCOM,

assigned the Air Force the lead role in developing the long-range missile capability for PGS in

mid-2008.46

According to DOD, the CSM was, at that time, the “lead design to demonstrate a

possible materiel solution for the CPGS warfighting capability gap.”47

42 Michael Sirak, “Air Force Envisions Mid-Term, Prompt Global Strike Missile,” Defense Daily, July 7, 2006. 43 Carlos Munez, “Services Collaborate on Long-Term Prompt Global Strike Study.” Inside the Navy, September 10,

2007. 44 Emelie Rutherford, “AoA for Prompt Global Strike to go to JROC this Summer, Chilton Says,” Defense Daily,

March 5, 2008. 45 Elaine M. Grossman. “‘Conventional Strike Missile’ Proposed as Midterm Global Option,” Inside Defense, April 6,

2006. 46 Elaine M. Grossman, “Chilton Shifts Prompt Strike Priority to the Air Force,” Global Security Newswire, September

3, 2008. 47 U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research Development, Test and Evaluation.

Defense Wide, Washington, DC, February 2010, p. 257, http://comptroller.defense.gov/defbudget/fy2011/

budget_justification/pdfs/03_RDT_and_E/OSD%20RDTE_PB_2011_Volume%203B.pdf.



According to DOD, the CSM would have been a land-based system that used boost-glide

technologies to deliver conventional payloads at near-global ranges, and to provide effects on

target within minutes to hours of launch.48

The CSM would not follow the standard ballistic

trajectory of nuclear-armed ballistic missiles. Its booster would launch with a lower-profile, or

depressed, trajectory. The payload delivery vehicle (PDV), after separating from the launch

vehicle, could maneuver to its target. This would not only provide it with high accuracy, it would

be able to maneuver to avoid overflight of third-party countries.49

With these capabilities, the

CSM may mitigate some of the concerns about nuclear ambiguity raised by Congress during its

review of the CTM program.

According to Air Force plans, the CSM would have combined the Minotaur IV launch vehicle

described above with a hypersonic payload delivery vehicle (PDV).50

The first PDV would have

been a weaponized version of the DARPA/Air Force HTV-2 vehicle. As an alternative, it could

have been based on the Army advanced hypersonic weapon (AHW) that is described below.51

Press reports indicate that General Chilton initially hoped that the CSM would reach an initial

operational capability, with one missile on alert and two spares, by 2012. He later indicated that

the missile might be ready for deployment in 2015.52

These dates slipped, however, and,

according to DOD officials, the program did not have an official deployment date because DOD

had not concluded the research, development, and testing programs for the possible reentry

bodies. DOD was not prepared to decide which technology would be deployed until the reentry

bodies have been tested in five demonstration flights. This has not yet happened, and may not

happen until later in the decade.53

Hypersonic Test Vehicle (HTV-2)

DARPA indicated that the goal for the HTV-2 program was to develop a vehicle that could launch

into the Earth’s upper atmosphere and descend across the Pacific Ocean with speeds of more than

13,000 miles per hour. It should be designed to travel from Vandenberg Air Force Base to a target

near Kwajalein Atoll in the Pacific Ocean in 30 minutes. Lockheed Martin Corporation developed

the HTV-2, using many of the concepts and technologies developed for the E2 warhead.54

DARPA planned to acquire and test two vehicles. The Air Force also contracted with Lockheed

Martin to produce a third vehicle, which the Air Force planned to use as the PDV in a test of the

CSM’s ability to deliver a weapon to the target.

48 Major Jason E. Seyer, “Adding the Conventional Strike Missile to the US’s Deterrence Toolkit,” High Frontier,

February 2009. 49 Major Jason E. Seyer, “Adding the Conventional Strike Missile to the US’s Deterrence Toolkit,” High Frontier,

February 2009. 50 Grossman, Elaine M. “U.S. Military Eyes Fielding “Prompt Global Strike” Weapon by 2015,” Global Security

Newswire, July 1, 2009. 51 According to DOD, “the Army Hypersonic Glide Body (HGB) design provides an alternative risk reduction path

within the Air Force CSM concept.” See U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research

Development, Test and Evaluation. Defense Wide, Washington, DC, February 2010, p. 257,

http://comptroller.defense.gov/defbudget/fy2011/budget_justification/pdfs/03_RDT_and_E/

OSD%20RDTE_PB_2011_Volume%203B.pdf. 52 Elaine M. Grossman, “U.S. Military Eyes Fielding ‘Prompt Global Strike’ Weapon by 2015,” Global Security

Newswire, July 1, 2009. 53 Elaine M. Grossman, “Cost to Test Global-Strike Missile could Reach $500 Million,” Global Security Newswire,

March 15, 2010. 54 Defense Advanced Research Projects Agency (DARPA_, Falcon Hypersonic Technology Vehicle 2 (HTV-2), Fact

Sheet, Washington, DC, April 15, 2010.



In FY2008, when Congress established the defense-wide conventional prompt global strike

program with a budget of $100 million, DOD allocated $56 million to hypersonic glide

experiments and concept demonstration development. This is the portion of the budget that

supports the development and testing of the HTV-2. This program area received an additional $42

million in FY2009 and $90 million in FY2010. The Obama Administration requested an

additional $136.5 million for this program area in FY2011. According to DOD’s budget request, it

planned to use these funds to conduct the HTV-2 flight experiments, finalize design concept for

the CSM payload delivery vehicle, complete qualification of a Minotaur launch vehicle for a

CPGS mission, and mature/demonstrate technologies associated with the high speed

demonstration of conventional munitions. DOD has also indicated that it would use funding in

this program area to procure the PDV warhead and booster that the Air Force will use in the

planned CSM “weaponized” flight test.55

On April 22, 2010, DOD conducted its first test of the HTV-2 vehicle, launching it from

Vandenberg Air Force Base in California. It launched the HTV-2 on a Minotaur IV rocket, in its

“lite” configuration, with only the three Peacekeeper stages, and without the new fourth stage.

This reduced the range of the missile in response to test mission limitations.56

According to

DARPA, its preliminary results show that the HTV-2 achieved controlled flight in the atmosphere

before telemetry was lost nine minutes after liftoff.57

Media reports deemed the launch to be a

partial success, noting that the boost mechanism performed a successful launch. The detachment

was also successful, though the glider itself failed to fly the full time of 30 minutes and total

distance of 4,100 nautical miles. According to press reports, DARPA was able to gather “a

significant amount of data” during the test.58

DOD reviewed the results of the April 2010 test, in

an effort to determine what caused the vehicle to fail during its flight.59

It also conducted a

number of wind tunnel tests and computer simulations to optimize the vehicle design and flight

trajectory before the second test.

DOD conducted a second test of the HTV-2 vehicle on August 10, 2011. According to DARPA,

the Minotaur missile successfully boosted the HTV-2 vehicle onto the desired trajectory and the

HTV-2 vehicle successfully separated from the booster and transitioned to its “Mach 20

aerodynamic flight.” However, the HTV-2 then “experienced a flight anomaly post perigee.” This

prompted the system to make a “controlled descent and splash down in the ocean.”60

In other

words, DARPA lost contact with the HTV-2 vehicle after it began its independent flight along its

glide trajectory, and the vehicle crashed into the ocean. DARPA said that the test had important

successes, with the launching, separation, and initial trajectory of the vehicle, and that it collected

55 U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research Development, Test and Evaluation.

Defense Wide, Washington, DC, February 2010, p. 261, http://comptroller.defense.gov/defbudget/fy2011/

budget_justification/pdfs/03_RDT_and_E/OSD%20RDTE_PB_2011_Volume%203B.pdf. 56 “Minotaur IV/HTV-2 Lifts Off,” Targeted News Service, May 20, 2010. 57 Defense Advanced Projects Agency (DARPA), Falcon HTV-2 Launch Test Hypersonic Vehicle Flight Capabilities,

Fact Sheet, Washington, DC, April 23, 2010. 58 Elaine M. Grossman, “Pentagon Nears Finding on Hypersonic Glider Test Failure,” Global Security Newswire,

August 19, 2010. 59 Elaine M. Grossman, “Pentagon Nears Finding on Hypersonic Glider Test Failure,” Global Security Newswire,

August 19, 2010. 60 Defense Advanced Research Projects Agency, DARPA Hypersonic Vehicle Splash Down Confirmed, Washington,

DC, August 14, 2011, http://www.darpa.mil/NewsEvents/Releases/2011/2011/09/

11_DARPA_HYPERSONIC_VEHICLE_SPLASH_DOWN_CONFIRMED.aspx.



significant data during the flight. However, it has not yet determined how to control the

aerodynamic portion of the flight, after the HTV-2 separates from its booster.61

According to DOD, in FY2011, it completed a finalized the design concept for the CSM payload

delivery vehicle and qualified the Minotaur launch vehicle for a CPGS mission analysis of launch

system infrastructure requirements utilizing other ballistic missile propulsion programs. However,

the combination of the poor test record and tight budget environment has undermined the future

of this program. DOD allocated $51.8 million to this program area in FY2012 and requested an

additional $49.5 million for FY2013. Congress added funding to the CPGS program area in

FY2013; after sequestration, the budget totaled $176.4 million. However, only $23 million of this

was allocated to the HTV-2 program. Further, in its FY2014, FY2015, FY2016, FY2017 budget

requests, DOD sought only $2 million for this program area. The FY2018 budget request includes

seeks only $1 million. According to the budget documents, these funds will allow DOD to

conduct studies to evaluate system alternatives, and to continue aerodynamic and weapon risk

reduction and technology maturation efforts through ground and wind tunnel tests. DOD does

not, however, plan to conduct any additional flight tests of the HTV-2 vehicle.

ArcLight

DARPA also, for a time, sought to design a new system, known as ArcLight, that could serve as

an alternative delivery vehicle for the PGS mission. The ArcLight program would use “a high-

tech missile based on the current standard missile 3 booster with a hypersonic glider that can

reach more than 2,300 miles to its target.”62

DOD budget documents from prior years indicate

that the ArcLight missile would have a range of around 2,000 nautical miles and might carry a

100-200 pound payload. The vehicle would be launched from the Navy’s Mark 41 vertical launch

system, on both submarines and surface ships. It would have a shorter range than either the

Trident missile or the Air Force CSM. As a result, it would require forward positioning of Navy

assets. DOD requested $2 million for the ArcLight program in FY2010 and $5 million in FY2011.

However, it seems to have terminated the program and has not requested any additional funding

in FY2012.

Army Advanced Hypersonic Weapon

The Army has also developed a hypersonic glide vehicle, known as the advanced hypersonic

weapon (AHW). Like the HTV-2, the AHW would use a hypersonic glider to deliver a

conventional payload, but could be deployed on a booster with a shorter range than HTV-2 and,

therefore, may need to be deployed forward, on land or at sea. It would be based on a conical

design, rather than the wedged-shape design of the HTV-2. Upon nearing a target, the weapon

would be able to maneuver and home in on target using precision guidance system.

Congress appropriated $1.5 million for the Army’s hypersonic glide body, now known as the

advanced hypersonic, weapon in FY2006, and added $8.9 million in FY2007.63

DOD allocated

$29 million of the combined fund for CPGS to the Army’s program in FY2008, $13.9 million in

FY2009, $46.9 million in FY2010, and $69 million for FY2011. Congress appropriated $91

million for this alternative in FY2012, and DOD requested an additional $42 million for FY2013.

As was noted above, Congress increased CPGS funding in FY2013, and, after sequestration, the

61 Thom Shanker, “Brief Test of Military Aircraft Said To Yield Much Data,” New York Times, August 12, 2011. 62 Craig Hooper, “New Navy Missile Could Hit Global Targets,” Military.com, July 8, 2010. 63 Elaine M. Grossman, “Army Eyes Advanced Hypersonic Weapon,” Inside Defense, January 5, 2007.



AHW portion of the budget received $147.8 million. Congress appropriated an additional $55

million for the AHW in FY2014, $90 million in FY2015, and $86 million in FY2016. The

FY2016 budget documents also indicated that DOD expected funding to increase steadily in the

next five years. Following this plan, DOD requested $174 million for the AHW, now known as

the Alternate Re-Entry System in FY2017 and $197.4 million in FY2018. The increase supports

planned flight tests in 2017 and 2019.

The Army conducted a successful flight test of the AHW on November 17, 2011.64

The system

launched from the Pacific Missile Range Facility in Hawaii, and used the strategic targets system

(STARS) booster stack, which is derived from the Navy’s Polaris ballistic missile. According to

press reports, the vehicle traveled 2,400 miles, from the Pacific Missile Range Facility in Hawaii

to Kwajalein Atoll. The test collected data on hypersonic boost-glide technologies and test range

performance. The mission also tested the thermal protection technologies for the vehicle, an area

where concerns exist because of the high temperatures generated during flight.

DOD initially indicated that the AHW program was a “risk mitigation effort in support of the Air

Force CPGS project” and is intended to “develop and demonstrate the capability of an alternative

payload delivery vehicle (APDV) through a two-flight test schedule.” However, after the HTV-2

experienced difficulties in both its flight tests, and the AHW succeeded in its first test, this system

appeared to be the leading contender for the hypersonic glider portion of a boost-glide

conventional prompt strike system.

DOD conducted a second flight test of this system on August 25, 2014.65

During this test, DOD

launched the vehicle from the Kodiak Launch Complex off Alaska and planned to fly it to the test

range at Kwajelein Atoll in the South Pacific.66

However, controllers destroyed the weapon four

seconds after launch after detecting problems with the STARS booster. With this failure early in

the flight, the test provided no information about AHW glider and did nothing to advance the

program.67

Reports indicate that the Army has determined that failure was caused by an “external

thermal protective cover designed to regulate motor temperature,” which “interfered with the

launch vehicle steering assembly.”68

Neither the booster nor the hypersonic vehicle contributed to

the test’s failure.

DOD scheduled a third flight experiment, using a “scaled” version of the Advanced Hypersonic

Weapon for 2017. Although the test was conducted from land in Hawaii, the scaled version of the

vehicle was sized to fit on a submarine-launched ballistic missile. As is noted below, this test was

conducted, successfully, in late October, 2017.

Navy Programs

Reentry Vehicle Research

In FY2003, the Navy requested funding for research on a new type of guided reentry vehicle that

could significantly improve the accuracy of the Trident II (D-5) missiles. This program, known as

64 Ann Roosevelt, “First Test Flight Successful for Advanced Hypersonic Weapon Vehicle,” Defense Daily, November

18, 2011, p. 6. 65 Colin Clark, “Hypersonic Weapons Face Major Milestone in August Test,” Breaking Defense, March 18, 2014. 66 Bill Gertz, “Army Hypersonic Missile Fails in Second Test,” Washington Free Beacon, August 25, 2014. 67 Andrea Shalal and David Alexander, “Experimental U.S. Hypersonic Weapon Destroyed Seconds After Launch,”

Reuters, August 25, 2014. 68 Jason Sherman, “DOD Plans FY-17 ‘Flight Experiment’ Of Hypersonic Weapon,” Inside Defense, February 5, 2015.



the enhanced effectiveness (E2) initiative, included an initial funding request of $30 million, a

three-year study, and a full-scale flight test in early 2007.69

Congress rejected the initial funding

request in FY2003 and FY2004, but Lockheed Martin Corporation, the contractor pursuing the

study, continued with a low level of research into this system.

The E2 reentry vehicle would have integrated the existing inertial measurement unit (IMU)

guidance system (the system currently used to guide long-range ballistic missiles) with global

positioning system (GPS) technologies so that the reentry vehicle could receive guidance updates

during its flight.70

A standard MK4 reentry vehicle, which is the reentry vehicle deployed on

many Trident SLBMs, would be modified with a flap-based steering system, allowing it to

maneuver when approaching its target to improve its accuracy and increase its angle of

penetration. This steering system, which the Navy referred to as a “backpack extension,” would

increase the size of the reentry vehicle, making it comparable in size to the MK5 reentry vehicle

that is also deployed on Trident missiles. The E2 warhead could possibly have provided Trident

missiles with the accuracy to strike within 10 meters of their intended, stationary targets. This

accuracy would improve the lethality of the nuclear warheads, but it would also permit the

missiles to destroy some types of targets with conventional warheads.71

Lockheed Martin flew these reentry vehicles in test flights of Trident missiles.72

In a test

conducted in 2002, it demonstrated that the new reentry vehicle could steer toward a target and

strike with improved accuracy. In a test conducted in early 2005, a modified version of its reentry

vehicle demonstrated that it could not only steer toward a target with improved accuracy, but also

slow down and “control the impact conditions,” capabilities that would be needed for the delivery

of some types of conventional warheads to their targets. Lockheed estimated that, if the program

received funding from Congress beginning in FY2006, its reentry vehicle could enter production

in FY2010 and achieve an initial operational capability in 2011. The Navy, however, did not seek

funding for this program in FY2004, FY2005, or FY2006.

The Lockheed Martin reentry vehicle became a part of the plan to deploy conventional warheads

on Trident submarine-launched ballistic missiles, and was included in the Navy’s budget request

for FY2007 and FY2008. The budget request for FY2008 indicated that most of the work needed

to design and develop the reentry vehicle for the conventional Trident could have been completed

in FY2008, with an additional $20 million request planned for FY2009.73

The FY2008 funding

would have supported, among other things, efforts to finalize the guidance and flap system on the

maneuvering body extension of the reentry body, design an interface between the new guidance

system and the missile system flight controls, begin development of a conventional payload that

69 Norris, Robert S. and Hans M. Kristensen. “U.S. Nuclear Forces 2005,” Bulletin of the Atomic Scientists,

January/February 2005, pp. 73-75. 70 According to the Defense Science Board Task Force on Future Strategic Strike Forces, the IMU would guide the

missile in its early phases, but the reentry body would receive a GPS update during its exoatmospheric flight; it would

then use the IMU and control flaps to steer the warhead with GPS-like accuracy during atmospheric reentry. See U.S.

Department of Defense. Report of the Defense Science Board Task Force on Future Strategic Strike Forces. February

2004. pp. 5-7. 71 Grossman, Elaine M., “Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs,” Inside the

Pentagon, June 27, 2002. p. 1. See also, Robert S. Norris and Hans M. Kristensen, “U.S. Nuclear Forces 2005,”

Bulletin of the Atomic Scientists, January/February 2005, pp. 73-75. 72 Krivich, David, Director, SMP Advanced Programs and Business Development, Lockheed Martin Space Systems

Company, Update on Precision Conventional Ballistic Missile Global Strike Capabilities, Briefing to the Defense

Science Board Task Force on Nuclear Capabilities, July 22, 2005. 73 Department of the Navy, Fiscal Year 2008/2009 Budget Estimates, Justification of Estimates, February 2007,

Research, Development, Test, and Evaluation, Navy Budget Activity 4.



could fit within the reentry body, and initiate efforts to modify existing facilities so that they

could test the conventional Trident modification (CTM) designs. Congress, however, rejected

these funding requests amid concerns about the rationale for the program and the potential for

misunderstanding if the weapons were used in a conflict.

If it had received the requested funding in FY2008, and proceeded with the expected work plan,

the Navy planned to conducted system development and demonstration activities in FY2008 and

FY2009, and planned to begin production and deployment in FY2010. With this timeline, the

system would have reached its full operational capability by the end of 2012. However, as is

noted below, Congress rejected the Navy’s funding request for FY2008 and restructured the PGS

program.

DOD allocated a portion of the combined funding for the PGS mission to this program area in

FY2009. In documents submitted with its FY2009 budget request, the Navy sought funding for a

2009 flight experiment “using a Life Extension Test Bed (LETB-2) reentry body on a currently

planned Trident D-5 missile test.”74

The LETB-2 is essentially the same as the maneuvering

reentry body, described above, that evolved from the E2 reentry vehicle program. Even though

the test bed would fly on a Trident missile test, the Navy contended that the technology would be

applicable to any conventional ballistic missile, and, therefore, was not prohibited by the FY2008

legislation. Moreover, according to some reports, the test was funded separately, outside the

combined conventional prompt global strike (CPGS) account.75

DOD indicated that during

FY2012, it would continue to adapt the LETB reentry bodies as a part of its test-range

development plans.

The Navy also requested, in its FY2009 budget, funding for a reentry body for a conventional

ballistic missiles. This program, known as the Medium Lift Reentry Body, would be too large to

fit on a Trident missile but could carry the warhead on the intermediate range submarine-launched

ballistic missile (described below). It would carry a tungsten-rod (“flechette”) warhead, which

would be designed to destroy area targets such as airfields and military bases.

Conventional Trident Modification

The Navy began to speak publicly about its plans for the conventional Trident modification

(CTM) in early March 2006. Under this concept, the Navy planned to deploy each of its 12

Trident submarines on patrol (two would be in overhaul at any given time) with two missiles

equipped to carry four conventional warheads each. The remaining 22 missiles on each submarine

would continue to carry nuclear warheads, and the submarines would continue to patrol in areas

that would allow them to reach targets specified in the nuclear war plan, although the patrol areas

could be adjusted to accommodate targeting requirements for the CTM. Only four submarines

would be within range of their targets, with two in the Pacific Ocean and two in the Atlantic

Ocean. Consequently, only eight conventional missiles would be available for use at any time,

and only one or two of the submarines would likely be within range of the targets specified for

attack with conventional ballistic missiles.76

The Navy considered two types of warheads for the CTM program in the near term. One warhead

would be designed to destroy or disable area targets like airfields or buildings, using a reentry

74 Elaine M. Grossman, “Controversial Missile Idea Lingers,” Global Security Newswire, March 20, 2008. 75 Elaine M. Grossman, “U.S. Navy Plans August Test for Conventional Trident-Related Technology,” Global Security

Newswire, May 21, 2009. 76 Ibid.



vehicle loaded with tungsten rods—known as flechettes—that would rain down on the target and

destroy everything within an area of up to 3,000 square feet. The other might be able to destroy

hardened targets, like underground bunkers or reinforced structures, if it were accurate enough to

strike very close to the target. Each would be deployed within the reentry body developed and

tested under the E2 program. The Navy also explored, for possible future deployment,

technologies that might be able to penetrate to destroy hardened, buried targets.

The Navy argued that these warheads would have provided the Navy with the ability to contribute

to the prompt global strike mission in the near term, a goal that was identified in the 2006 QDR.

The report indicated that the Navy would seek to deploy an “initial capability to deliver precision-

guided conventional warheads using long-range Trident” missiles within two years,77

although

many expected it to take four years to field the full complement of 96 warheads. The capability,

even when fully deployed, would be limited by the small number of available warheads. Hence, it

seems likely that the Pentagon would have planned to use these missiles only in limited

circumstances to meet specific goals.

The budget the Navy prepared for FY2007 included a total of $503 million over five years, with

$127 million for FY2007, $225 million for FY2008, $118 million for FY2009, and $33 million

for FY2010.78

As noted below, Congress denied the funding request in FY2007. The Pentagon

requested a total of $175.4 million for FY2008, but Congress did not approve the specific funding

again. Instead, as is noted in more detail below, it provided research and development funding for

a more general category of “prompt global strike” initiatives.

Submarine-Launched Intermediate-Range Global Strike

The Navy has also studied the possible development and deployment of a submarine-launched

intermediate-range ballistic missile (SLIRBM). It requested industry participation in the study in

mid-2003, and planned to conduct two static test-firings of a prototype rocket engine in 2005.79

According to the Defense Science Board Task Force, this missile might have delivered a 2,000-

pound payload over a 1,500-mile range,80

with an accuracy of less than 5 meters. This would

allow the missile to reach its target in less than 15 minutes.81

Reports of the initial studies into this

concept indicated that this proposed missile could carry either nuclear or conventional warheads,

allowing it to contribute to the missions requiring prompt, long-range strike capabilities.82

These

missiles could also be deployed on nuclear-capable Trident submarines, with 2 or 3 missiles

deployed in up to 22 of the submarine’s launch tubes, for a total of 66 missiles per submarine.

However, as the concept emerged, it became evident that the missiles would have been deployed,

with perhaps two per launch tube, in the four Ohio-class submarines that have already been

converted to carry conventional cruise missiles and other nonnuclear weaponry.

Congress appropriated $10 million for the SLIRBM in FY2005 and $7.2 million in FY2006. In

the House, the Defense Appropriations Subcommittee added $2 million for this effort in FY2007,

77 U.S. Department of Defense, Quadrennial Defense Review Report, February 6, 2006, p. 50. 78 Grossman, Elaine, “Pentagon Wants Early Start on Conventional Missiles for Subs.” InsideDefense.Com, January 20,

2006. See also, Grossman, “Facing Doubts, Pentagon Readies Pitch for New Sub-launched Missile.” Inside the

Pentagon. March 9, 2006. 79 Norris, Robert S. and Hans M. Kristensen, “U.S. Nuclear Forces 2005,” Bulletin of the Atomic Scientists,

January/February 2005, pp. 73-75. 80 A Trident II (D-5) missile can deliver its warheads over a range of 4,000 miles. 81 Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004, pp. 5-12. 82 Koch, Andrew. “U.S. Considers Major Changes to Strategic Weapons,” Jane’s Defence Weekly, September 27, 2003.



but the conference committee provided only $1.3 million. The Pentagon did not request any

additional funding for this program for FY2008, but it did indicate that prior-years’ funding

would be used to continue funding efforts that will demonstrate the affordability and feasibility of

this concept.

The Pentagon remained interested in this concept in 2008 and considered allocating $120 million

in FY2008 and $140 million in FY2009 to pursue a medium-range “Submarine-launched Global

Strike Missile” with a range of 2,000-3,000 nautical miles.83

However, as is noted below,

Congress eliminated Navy funding for conventional prompt global strike programs in FY2008

and combined all DOD funding in a single defense-wide account. This account did not provide

any funds to this missile, and the Navy did not request any additional funds in its budget in

subsequent years.

The Pentagon reasserted its interest in deploying a prompt strike capability on submarines in

January 2012, in its report on defense budget priorities and choices. It noted that, as a part of the

U.S. effort to “rebalance” U.S. forces toward the Asia-Pacific and Middle East regions, the

United States would need to invest in capabilities “required to maintain our military’s continued

freedom of action in the face of new technologies designed to frustrate access advantages.” The

list of such technologies included the “design of a conventional prompt strike option from

submarines.”84

In his briefing after the release of this document, Secretary of Defense Leon

Panetta linked this effort with a program to provide the Virginia-class attack submarines with the

capability to carry more conventional cruise missiles. The same mid-body launch tubes, known as

the Virginia payload module, that might carry more cruise missiles might also carry conventional

boost-glide systems.85

During the Obama Administration, DOD did not specify whether it would deploy a PGS system

on land or at sea. It did, however, leave open the option of deploying the systems at sea, so that it

could pursue technologies that would reduce the cost and risk of the program, as it developed

both the booster and the hypersonic glider technologies, even if they came with a reduced range.

Moreover, unlike with the conventional Trident program, with an intermediate-range PGS system,

DOD would not install conventional warheads on missiles that had been equipped with nuclear

warheads. In addition, the boosters would travel on a flatter trajectory, and would likely have a

different launch profile and a different number of stages, than the existing Trident missiles.

According to General Martin Dempsey, the former Chairman of the Joint Chiefs of Staff, these

differences in technology would likely mitigate the risk of an adversary observing the launch and

concluding, incorrectly, that the United States had launched an attack with a nuclear-armed

missile.86

DOD has moved forward with the sea-based option for the conventional prompt strike mission. In

its FY2015 budget request, DOD noted that, during FY2013, it began to review a new series of

demonstrations within the Alternate Re-Entry System program area by the Navy’s strategic

systems program. It also stated that it would begin critical design reviews and begin to assemble a

83 Grossman, Elaine, M., “Midrange Missile May be Backup to Modified Trident,” Global Security Newswire,

September 21, 2007. 84 U.S. Department of Defense, Defense Budget Priorities and Choices, Washington, DC, January 2012, p. 5,

http://www.defense.gov/news/Defense_Budget_Priorities.pdf. 85 Christopher P. Caves, “Subs May Serve Attack, Guided Missile Functions,” Navy Times, October 15, 2011,

http://www.navytimes.com/news/2011/10/navy-dual-use-submarines-attack-guided-missile-101511w/. 86 U.S. Department of Defense, Major Budget Decisions Briefing From the Pentagon, Washington, DC, January 26,

2012, http://www.defense.gov/transcripts/transcript.aspx?transcriptid=4962.



vehicle for a Navy flight test in FY2015. The FY2014 budget documents noted that a flight test of

Navy variant of a conventional prompt strike system, which could be a reference to the

intermediate-range option deployed on Virginia-class submarines, might occur before the end of

2016, but this was delayed until October 2017, when DOD conducted a successful test of a

booster and glider that could be deployed on a submarine.

The October 30 test, identified as Flight Experiment 1, flew more than 2,000 nautical miles from

Hawaii to the Marshall Islands. Although the flight was launched from land, the test was executed

by the Navy’s Strategic Systems Programs office. The Pentagon estimated that the test cost $160

million, and, while DOD did not identify the specific objectives or results of the test, Vice

Admiral Terry Benedict, head of the Navy's Strategic System Programs office, declared the event

a “success.”87

In addition, in a speech a few days after the test, Admiral Benedict indicated that

the Navy could eventually deploy the conventional strike system on either Ohio class ballistic

missile submarines that have been converted to launch cruise missiles (known as SSGNs) or

Virginia class attack submarines equipped the Virginia payload module.88

The DOD budget request for FY2019 indicates that it will conduct a second flight test by the end

of FY2020. The budget request also contains no funds for the OSD-wide account for Prompt

Global Strike Capability Development after FY2019 and indicates that “Conventional Prompt

Strike program and funding transfers to the Navy” starting in FY2020. Moreover, funding for the

program is expected to increase significantly, from a request for $278 million in FY2019 to a

request for $478 million in FY2022, for a total of $1.9 billion between FY2019 and FY2022. This

is more than twice the amount expected over a five-year period in the FY2018 budget request.

Legislative Activity

Congress first considered the Administration’s plans to develop conventional warheads for

possible deployment on long-range ballistic missiles in FY2003. Since then, it has demonstrated

some support for and some skepticism about the plans.

FY2003 and FY2004

As was noted above, the Navy requested $30 million for its E2 program in FY2003 and FY2004.

In each case, this was to be the initial year of funding in a three-year study. Congress refused the

Navy’s request in both years.

The Bush Administration requested $12.2 million in research and development funding for the

common aero vehicle (CAV) program in FY2004. The House, in its version of H.R. 1588, the

FY2004 National Defense Authorization Act, nearly doubled the authorized funding to $24.2

million. The Senate provided the requested amount, and the conference committee split the

difference, authorizing $17.025 million. Although Congress supported the Administration’s

request for funding, the House had shown concerns about the possibility that U.S. launches of

ballistic missiles armed with conventional warheads could be misinterpreted as nonconventional

launches by nations who might monitor U.S. military activity—a concern, particularly, to Russia

and China. Hence, the House required that the Air Force submit a report on the concept of

87 Jason Sherman, “DOD flies experimental hypersonic payload; claims success,” Inside Defense, November 2, 2017.

https://insidedefense.com/inside-army/dod-flies-experimental-hypersonic-payload-claims-success. 88 Jason Sherman and Lee Hudson, “Navy reveals plans to put hypersonic strike weapons on submarines,” Inside

Defense, November 3, 2017, https://insidedefense.com/inside-navy/navy-reveals-plans-put-hypersonic-strike-weapons-

submarines.



operations for the CAV that would address questions about the potential for misinterpretation of

the launches. This reporting requirement remained in the final version of the National Defense

Authorization Act for Fiscal Year 2004 (P.L. 108-136).

The National Defense Authorization Act for Fiscal Year 2004 (P.L. 108-136, §1032) also contains

a requirement for an annual report describing “an integrated plan for developing, deploying, and

sustaining a prompt global strike capability.” Congress mandated that the plan should include

information on, among other things, the types of targets for long-range strike assets, the

capabilities desired for these assets, an assessment of the command and control, intelligence, and

surveillance capabilities necessary to support the PGS mission, integration with tactical missions,

and cost and schedule for achieving the mission. In the conference report (H.Rept. 108-354),

Congress noted that its interest in these issues derived from the 2001 Nuclear Posture Review and

its focus on integrating nuclear and conventional strike capabilities to reduce reliance on nuclear

weapons. It indicated that it saw a need for further analysis of future system requirements, along

with a comprehensive effort to link planning and programs in a PGS roadmap to achieve a

coherent force structure. Hence, although the Air Force considered the NPR objective of

integrating nuclear and conventional strike forces as a separate mission and separate concept from

PGS, Congress, initially at least, blended both into the request for a new report.

The Air Force submitted its report on the CAV concept of operations to Congress in February

2004. This report offered several suggestions for measures the United States could take to reduce

the possibility of misinterpretation if the United States were to deploy, and employ, ballistic

missiles with conventional warheads. Many of the measures discussed in this report are

summarized below, under “Issues for Congress.”

FY2005

The Bush Administration requested $16.4 million for research and development on the CAV in

FY2005. Congress again increased this funding level, appropriating $21.6 million for the

development of the CAV. However, in July 2004, with passage of the FY2005 Defense

Appropriations Act (H.R. 4613, P.L. 108-287), Congress repeated its concerns about the potential

for misinterpretation. In the report on the Defense appropriations bill, Congress questioned

whether there were safeguards in place to guarantee that other nuclear weapons states did not

misinterpret the intent or use of ballistic missiles armed with CAV. In response to these concerns,

the report stated that funds provided for CAV could only be used for non-weapons-related

research on hypersonic technologies, including studies into microsatellites or other satellite

launch requirements. Congress specified that the funds could not be used to “develop, integrate,

or test a CAV variant that includes any nuclear or conventional weapons.” Congress also

indicated that the funds could not be used to “develop, integrate, or test a CAV for launch on any

ICBM or SLBM.” Congress would consider expanding the scope of this program in future years

if safeguards negotiated among international partners were put into place.89

FY2006 and FY2007

The Bush Administration requested $27.2 million for CAV in FY2006. In response to the

restrictions in the FY2005 Defense Appropriations Act, it restructured the program, and

redesignated the CAV as the hypersonic technology vehicle. This new program excluded any

development of weapons capabilities for the CAV. Congress approved the requested funding in

89 U.S. Congress, House, Making Appropriations for the Department of Defense for the Fiscal Year Ending September

30, 2005, and For Other Purposes, Conference Report to Accompany H.R. 4613, H.Rept. 108-622, p. 240.



the FY2006 Defense Appropriations Act and did not impose any new restrictions. The Bush

Administration requested, and Congress appropriated, an additional $33.4 million for CAV in its

FY2007 budget. Congress also appropriated $12 million for the Air Force conventional ballistic

missile (CBM) program, which was exploring the possible use of a modified Minuteman missile

as a mid-term option for the PGS mission.

The budget projections in the FY2006 budget request demonstrated how costs could have

increased if the Air Force continued to pursue the CAV program. The budget requests were

projected to be between $31 million and $39 million each year for the next three years, but they

were then projected to rise to $92 million in FY2010 and $94 million in FY2011. This sharp

increase reflected an expected change in the program from research and development to

production and deployment at the end of the decade. This change would require that the Air Force

address and resolve congressional concerns about the potential for misunderstandings with the

launch of ballistic missiles armed with conventional warheads.

The budget projection for the CAV also indicated that the CAV would not have provided a near-

term solution to the PGS mission needs. It would not have been available until the middle of the

next decade, even though, as was evident in the 2006 QDR, the Pentagon was interested in

meeting the needs of the PGS mission in the near term. This resulted in a growing interest in the

Navy’s CTM program.

The Navy’s FY2007 budget included $127 million for the conventional Trident modification. The

request separated into three categories. The budget included $38 million for the CTM within the

much larger ($957.6 million) budget for Trident II missile modifications; $12 million for strategic

missile systems equipment to support the CTM; and $77 million for the development of an

advanced strike capability that would demonstrate the feasibility of the CTM concept.

Neither the House nor the Senate Armed Services committees authorized the Administration’s

request in their versions of the FY2007 Defense authorization bills (S. 2766 and S.Rept. 109-254;

H.R. 5122 and H.Rept. 109-452). Both committees noted their concerns about the possibility that

nations, such as Russia, might misunderstand the launch of a conventional Trident missile and

determine that they were under attack from U.S. nuclear weapons. Both committees requested

reports from the Administration that would address a range of issues raised by this prospective

program. The Senate Armed Services Committee withheld $95 million of the Administration’s

request, pending completion of the report. It authorized the use of $20 million for the preparation

of the report and $32 million for research and development on technologies that would support

the Trident modification. It specified that the money could not be used on the CTM program

itself. The full Senate accepted the committee’s position. The House Armed Services Committee

eliminated the $38 million for CTM in the Trident II modification budget and the $12 million for

strategic missile systems equipment. It also reduced by $47 million the Navy’s request for

funding for the CTM program, leaving $30 million for this effort.

The conference committee, in its report (H.Rept. 109-702, §219) adopted the reporting

requirements included in the Senate bill, but, instead of fencing the funding pending completion

of the report, accepted the House’s reduction in CTM funding. Therefore, as was the case in the

House bill, the conference report included only $30 million for research and development into an

advanced strike capability that would support the CTM concept.

The House and Senate appropriations bills also rejected the Administration’s request for funding

for the CTM program. Following the HASC, the Defense Appropriations subcommittee in the

House eliminated all but $30 million in research and development funding. It also raised

questions about the feasibility of the proposed schedule for the program and questioned whether

the decision to move forward immediately would pre-judge the outcome of the PGS AOA study.



In the Senate, the Defense Appropriations Subcommittee eliminated all funding for the CTM

program, and provided $5 million for the National Academy of Sciences to analyze the mission

requirement and recommend alternatives. The conference report on the Defense Appropriations

Act (H.Rept. 109-676) retained the Senate provision that funded $5 million for a report from the

National Academy of Sciences. It also included $20 million in Research, Development, Test and

Evaluation funds for research that would focus on those “developmental items which are common

to all the global strike alternatives.”

FY2008

The President’s budget request for FY2008 included continued funding of $32.8 million for the

CAV. Congress did not approve this request, but in both the authorization and appropriations bills,

transferred this funding to a new, integrated account for Prompt Global Strike Research. Congress

also eliminated separate funding of $50 million for other elements of the FALCON program,

rolling them into the new account as well. As is discussed in more detail below, the total funding

for this new account was set at $100 million for FY2008, less than half of the requested funding

for all the programs that were combined in the new account. The Pentagon has objected to this

transfer, noting that the elimination of the specific line items and the overall reduction in funding

would lead to the termination of the FALCON program and the cancellation of several planned

flight tests for the CAV. Although the Pentagon eventually accepted the idea of a combined

program for PGS research, it suggested that the total budget be set at $208 million, an amount

equal to the total proposed for the combined programs, so that each could continue to receive the

required level of investment.90

Congress did not accept this appeal, and the conference reports on

both the authorization (H.R. 1585, H.Rept. 110-477) and appropriations (P.L. 110-116, H.Rept.

110-434) bills limited the funding to $100 million.

The President’s budget for FY2008 also included a total of $175.4 million for the CTM program.

This request included $36 million, within the much larger budget of just over $1 billion for

Trident II modifications, to begin modifying the Trident II missiles to carry conventional

warheads. Congress had denied all funding for this purpose in FY2007. It also included $13

million in strategic systems missile equipment, which would be used to begin modifying Trident

submarines to carry the conventional missile. Congress had also denied this funding in FY2007.

Finally, the budget included $126.4 million to develop advanced strike capabilities under the

“Hard and Deeply Buried Target Defeat System Program” area. This funding is allocated to

continue research and development into reentry vehicle technologies for the conventional Trident

modification. Congress had appropriated only $20 million for this effort in FY2007, even though

the budget had requested $77 million.

The House Armed Services Committee, in its version of the FY2008 Defense authorization bill

(H.R. 1585, H.Rept. 110-146), supported continued research, development, testing, and

evaluation of the conventional Trident concept, but prevented funds from being obligated or

expended for the operational deployment of the system. Specifically, it approved the request for

$126.4 million for continued research and development on the reentry vehicle, and authorized

$16 million for procurement, but reduced the budget request by $33 million, withholding all

funds for long-lead procurement. The Strategic Forces Subcommittee noted that it supported, in

general, the pursuit of technologies for the prompt global strike mission, but also noted that

questions remained about the concept of operations and the possibility for misunderstandings.

90 Department of Defense Budget Appeal, FY2008 Defense Appropriations Bill, October 15, 2007.



Hence, it sought to slow the program until the National Academy of Sciences completed its

report.

The Senate Armed Services Committee, in its version of the FY2008 Defense authorization bill

(S. 1547, S.Rept. 110-77), recommended that no funding be provided specifically for the CTM

program, and that all $208 million in PGS funding be transferred to PE 65104D8Z, to support

common prompt global strike concepts. The committee specifically indicated that this program

element should support a “coordinated look at a variety of kinetic non-nuclear concepts, as

necessary, to address the feasibility of a prompt global strike.” In its report, it noted that the

services were exploring several potential options for the PGS mission, and that research funded

through this program element could support, “in a coordinated fashion,” technologies that could

be common to several of these concepts. The committee also indicated that it believed any

resulting PGS capability should be clearly and unambiguously non-nuclear.

The conference committee adopted the Senate’s approach to combining the funding in a single

account, but, as the Appropriations Committee had done, limited the funding to $100 million

(H.Rept. 110-477). The conference report also required that the Under Secretary of Defense for

Acquisition, Technology, and Logistics submit a plan describing how DOD would obligate the

FY2008 funds (H.Rept. 110-477, §243). This funding profile indicates that Congress did not

reject the Prompt Global Strike concept completely, even though it had not accepted the

Administration’s sense of urgency or its certainty in the need for the CTM program in the near

term.

The House and Senate Appropriations Committees followed the “combined funding” model

established by the SASC. The House Appropriations Committee eliminated the specific funding

for the CTM, directed DOD to create a “prompt global strike program element within the

Research, Development, Test, and Evaluation, Defense-Wide appropriation,” and moved $100

million into this new account to “further the Department’s prompt global strike initiative” without

“limiting the Nation to a single option” at this point in time. Some of these funds could be used to

support research and development on the CTM concept. The committee also mandated that DOD

submit a report “that discusses the technology thrusts and investment objectives and outlines the

allocation of funding towards achieving these objectives.” The Senate Appropriations Committee,

in its version of the bill (H.R. 3222, S.Rept. 110-155) provided $125 million for the Research,

Development, Test and Evaluation, Defense-Wide account for prompt global strike mission. It

noted that these funds should be used “for engineering and development of alternatives to the

conventional TRIDENT missile program.” The final version of the FY2008 appropriations bill

limited the funding to $100 million (P.L. 110-181, H.Rept. 110-477).

FY2009

The Pentagon requested $117.6 million for the prompt global strike program element established

in the FY2008 Defense authorization and appropriations processes. It also submitted a report to

Congress, as required by the FY2008 Defense authorization bill (P.L. 110-181, H.Rept. 110-477,

§243), that outlined its plans for dividing up the FY2008 and FY2009 funding under the PGS

program element. In this report, DOD planned to spend $58 million in FY2008 and $70 million in

FY2009 on tests of the hypersonic glide vehicle emerging from the Air Force/DARPA program. It

also allotted $30 million in FY2008 and $40 million in FY2009 for alternative reentry systems

development, a reference to the Medium-Lift Reentry Body that could be deployed on a new sea-

based ballistic missile. Further, the report indicated that DOD would spend $6 million in FY2008

and $3 million in FY2009 on the LETB-2 demonstration described above.



The House Armed Services Committee, following the lead of the Strategic Forces Subcommittee,

approved this request. The Senate Armed Services Committee, however, added $30 million to this

amount, for a total of $147.6 million, in its version of the FY2009 Defense authorization bill (S.

3001). It indicated that these added funds, plus an additional $15 million in the budget request,

were to be allocated to R&D on the Army program developing an advanced hypersonic glide

vehicle—this program had not been included in the original budget request. However, in the final

version of the FY2009 Defense authorization bill, Congress provided the requested amount of

$117.6 million for the PGS account.

The Defense Subcommittee of the Senate Appropriations Committee deleted $43 million from the

PGS account, leaving $74.6 million. It removed the $40 million planned for work on the medium

lift reentry body and the $3 million allocated to the LETB-2 test bed program. In other words, it

rejected DOD’s plans to continue developing reentry technologies that could be deployed on

either the Trident missile or a new sea-based conventional ballistic missile. The final version of

the Defense appropriations bill, which was included in a larger consolidated appropriations bill,

included this reduction in funding. Further, the legislation specified that “not less than one-

fourth” of the funds provided, or $19 million, must be “available” for the advanced hypersonic

weapon under development by the Army.91

FY2010

The Department of Defense requested $166.9 million for the defense-wide conventional prompt

global strike program element. This request included $91.5 million for the DARPA/Air Force

hypersonic test vehicle, which the budget indicated would support efforts to continue hypersonic

technology development, to integrate the HTV-2 vehicles with Minotaur IV lite launch vehicles,

and to assess the progress of thermal and aerodynamic protection to the vehicles. The budget

request also included $46.9 million for the Army’s AHW program. The budget documents

indicated that this funding would support a first flight of the AHW in FY2011. Congress

authorized and appropriated the requested funds for FY2010.

FY2011

The Department of Defense requested $239.9 million for the combined Conventional Prompt

Global Strike program area in FY2011. The budget documents indicate that the Air Force

Conventional Strike Missile was still the leading design to fulfill the PGS mission, and the Army

AHW was deemed the alternative risk reduction plan to the CSM. The FY2011 budget allocated

$136.6 million to hypersonic glide experiments; this would support the continued development of

a payload delivery vehicle (PDV) for the conventional strike missile and development of the

Minotaur IV rocket booster. It would also support the integration of the HTV-2 delivery vehicle

and Minotaur IV missile, with two test flights of this CSM design expected in FY2011. The

budget also allocated $69 million to the Alternate Re-Entry System; this supports the

development of the hypersonic glide body (HGB) or the Army advanced hypersonic weapon. The

budget request would support one test flight of this technology in FY2011. The PGS fund also

allocated $24 million to Test Range Development and $10.3 million to administrative and study

costs, including the application of the Prompt Global Strike Analysis of Alternatives results.

Both the House and the Senate approved this request in their versions of the FY2011 Defense

authorization bill. The Senate Defense Appropriations Subcommittee, in its report on the FY2011

91 Elaine M. Grossman, “Strategic Arms Funds Tilt Conventional in 2009,” Global Security Newswire, November 7,

2008.



Defense appropriations bill, recommended full funding for the FY2011 request; however, it

directed that DOD could not obligate more than $189 million until it provided Congress with

details how it planned to restructure the program in light of the disappointing flight test results for

the HTV-2 vehicle.92

Congress, however, never completed work on the FY2011 budget request,

passing, instead, a continuing resolution through March 4, 2011. This bill held funding for most

government programs at the FY2010 level.

FY2012

The Department of Defense has requested $204.8 million for conventional prompt global strike

programs in FY2012. Although the original budget documents indicated that all of this funding is

allocated to hypersonic glide experiments and concept demonstration, this was an error and some

of the funding is alternative concepts and range support. According to the amended budget

request, $132 million is allocated to hypersonic glide experiments and concept demonstration,

while $51 million is allocated to the alternate payload delivery vehicle options, $12 million is

allocated to range support and $10 million for long-range studies. The budget request indicates

that the funding in FY2012 will be used to procure the PDV—the “weaponized” version of the

DARPA/Air Force HTV-2 vehicle—the warhead, and the booster to support the planned

“weaponized” test of the Air Force conventional strike missile.

When considering the Administration’s request for the CPGS program, the House Armed Services

Committee, in its version of the FY2012 Defense Authorization Bill, approved $179.8 million for

this program. In its report, the committee noted that the HTV-2 vehicle had not succeeded in its

2010 test flight, and that it was concerned about DOD’s intent to pursue a weaponized missile

system, or any material development decision, before it had demonstrated that the technology is

feasible. Moreover, the committee questioned DOD’s narrow focus on the Air Force CSM with

the HTV-2 payload as the solution to the CPGS problem. It noted that DOD had provided

briefings about “other potential conventional long-range strike capabilities that may be lower

cost, carry less technical risk, and provide a capability sooner than CSM.”93

As a result, the

committee encouraged DOD to pursue “a broader examination of the tradespace of CPGS

capabilities and concepts to meet warfighter requirements.” The Senate Armed Services

Committee, in its version of the FY2012 Defense Authorization Bill, approved the

Administration’s request for $204.8 million for CPGS. The conference committee, however,

adopted the House position, and authorized $179.8 million the CPGS program. It also altered the

allotments within the budget, providing $61.8 million for hypersonic glide experiment and

concepts development, the portion of the budget that supports the HTV-2, and $91 million for the

Alternate Re-Entry System, which supports the Army’s AHW program.

The House Appropriations Committee voted for a deep reduction in CPGS funding for FY2012,

approving only $104.8 million for the program. The committee’s report did not offer an

explanation for the $100 million reduction. The Senate Appropriations Committee appropriated

the requested $204.8 million. In the consolidated appropriations Act (H.R. 2055) for FY2012,

Congress matched the Defense Authorization Act and appropriated $179.8 million for CPGS. The

conference report noted that the reduction of $25 million was based on delays in the program

92 U.S. Congress, Senate Committee on Appropriations, Subcommittee on Defense, Defense Department

Appropriations Bill, 2011, Report, 111th Cong., 2nd sess., September 15, 2010, S.Rept. 111-295 (Washington: GPO,

2010), p. 177. 93 U.S. Congress, House Committee on Armed Services, National Defense Authorization Act for Fiscal Year 2012,

112th Cong., 1st sess., May 17, 2011, H.Rept. 112-78. p. 69.



caused by two failed HTV-2 flight tests. As a result, the conferees directed that the reduction in

funding should not come from the AHW vehicle, which had a successful flight test in late 2011.

FY2013

The Pentagon budget request for FY2013 included $110.383 million for the CPGS program.

Within this total, DOD requested $49.5 million for hypersonic glide experiment and concepts

development, $42 million for the Alternate Re-Entry System, $11 million for test range

development, and $7.9 million for studies. The House and Senate Armed Services Committees

both approved this amount in their versions of the FY2013 Defense Authorization Bills (H.R.

4310 and S. 3254); this amount was included in the final version of the FY2013 Defense

Authorization Act (P.L. 112-239). The House Armed Services Committee, in its report

accompanying the bill (H.Rept. 112-479), also directed the Secretary of Defense to provide a

report “detailing how the Department plans to use competition and integrate verification and

transparency measures as it develops and deploys CPGS capabilities.”

The Senate Appropriations Committee, in its version of the FY2013 Defense Appropriations Bill,

increased funding for the CPGS program from the requested $110.383 million to $200.383

million. In its report, the committee noted that the recommended an increase of $90 million so

that the Army could continue planning for and completing a second, longer-range flight test of

AHW. Congress included this amount in the Consolidated and Further Continuing Appropriations

Act, 2013 (P.L. 113-6), although, after sequestration, the final amount appropriated for FY2013

equaled $176.4 million. Within this total, $147.8 million was allocated to the Alternate Re-Entry

System, or AHW, and only $23 million was allocated to the HTV-2 hypersonic glide experiment

and concepts development area.

FY2014

The DOD budget request for FY2014 included $65.4 million for “prompt global strike capability

development.” Within this total, DOD allocated $2 million to hypersonic glide experiment and

concepts development, $55 million to the Alternate Re-Entry System and warhead engineering,

$5 million to test range development, and $3.4 million to studies.

A number of factors might account for both the reduction in the overall budget request and the

striking shift away from the HTV-2 program area. First, the budget documents indicate that

overall reductions in DOD spending have affected DOD’s ability to develop prompt global strike

capabilities. Specifically, DOD states that “the level of resourcing ... reflects iterative reductions

from efficiencies and budget reductions, which reduces the Department’s ability to develop

flexible responsive solutions to emerging war fighter needs.”94

The budget request also highlights

a shift in defense priorities, noting that DOD now plans to focus, with higher priority, on

“research and development of intermediate range concepts.”95

This may be a reference to DOD’s

interest, as noted in the January 2012 report on Defense Budget Priorities and Choices, in

designing “a conventional prompt strike option from submarines.”96

As was discussed above, this

94 U.S. Department of Defense, Fiscal Year (FY) 2014 President’s Budget Submission, Research, Development, Test &

Evaluation, Defense-Wide, Washington, DC, April 2013, pp. 3-581, http://comptroller.defense.gov/defbudget/fy2014/

budget_justification/pdfs/03_RDT_and_E/Office_of_the_Secretary_of_Defense_PB_2014.pdf. 95 Ibid., pp. 3-582. 96 U.S. Department of Defense, Defense Budget Priorities and Choices, Washington, DC, January 2012, p. 5,

http://www.defense.gov/news/Defense_Budget_Priorities.pdf.



option could lead to the deployment of intermediate-range ballistic missiles on Virginia-class

attack submarines.

Within the CPGS program, the shift in funding away from the hypersonic glide experiment and

toward the Alternate Re-Entry System indicates that DOD plans to seek an alternative to the

HTV-2 vehicle. Specifically, according to the budget documents, the Alternate Re-Entry System

“sub-project will test and evaluate alternative booster and delivery vehicle options and will assess

the feasibility of producing an affordable alternate solution to fill the CPGS capability gap.”97

Congress appropriated the requested funds, and maintained the requested division among

program areas, in the FY2014 National Defense Authorization Act (P.L. 113-66). However, in its

explanation of the bill, it requested that DOD submit a report addressing “the policy

considerations concerning any potential ambiguity problems regarding the launch of a

conventionally-armed missile from submarine platforms” and a description of the target sets that

a submarine-launched missile could reach but that could not be reached by missiles from other

platforms. It also requested that the report compare the costs of submarine-launched conventional

missiles with the costs of those launched by other platforms. Congress included this provision

because DOD’s renewed interest in the possible deployment of a sea-based CPGS capability

restored concerns about possible ambiguity issues.

FY2015

The DOD budget request for FY2015 includes $70.8 million for Prompt Global Strike Capability

Development. Within this total, DOD has allocated $2 million to the HTV-2 program—the

Hypersonic Glide Experiment and Conceptions Demonstration Support—line and $65.2 million

to the AHW—Alternate Re-Entry System/Warhead Engineering—line. The request also includes

$3.6 million for CPGS studies, but no additional funding for test range development. The House

and Senate Armed Services Committees both approved this amount in their versions of the

FY2015 National Defense Authorization Act, but Congress added $25 million to the program’s

appropriation, for a total of $95.6 million.

As in FY2014, the “level of resourcing” in the budget request reflects “reductions from

efficiencies and budget reductions.” DOD notes that this “reduces the Department’s ability to

develop flexible responsive solutions” to meet CPGS requirements. At the same time, the FY2015

budget request follows the trend set in FY2013 and FY2014, with the reduced emphasis on the

HTV-2 program and added funding flowing to the AHW glider program. Further, although this is

not reflected in the budget request, during testimony, DOD officials have referred to the program

as “conventional prompt strike,” dropping the emphasis on global. Taken together, these two

changes demonstrate that DOD’s focus may now be on developing an intermediate range

capability for the prompt strike mission.

FY2016

The DOD budget request for FY2016 includes $78.8 million for Prompt Global Strike Capability

Development. Within this total, DOD has allocated $2 million to the HTV-2 program—the

Hypersonic Glide Experiment and Conceptions Demonstration Support—line and $72.95 million

to the AHW—Alternate Re-Entry System/Warhead Engineering—line. The request also includes

$2.9 million for CPGS studies and $1 million for test range development. This request, along with

97 U.S. Department of Defense, Fiscal Year (FY) 2014 President’s Budget Submission, Research, Development, Test &

Evaluation, Defense-Wide, Washington, DC, April 2013, pp. 3-590.



the plans to move forward with the testing program for the AHW, further indicates that DOD has

essentially concluded the HTV-2 program and is moving toward the development and

deployment of a system using the AHW glider and an intermediate-range booster, possibly

deployed at sea.

The House, in its version of the FY2016 National Defense Authorization Act (H.R. 1735),

provided $108.8 million for Prompt Global Strike Capability Development. It added $15 million

for Concept Development by the Army of a CPGS option and $15 million for Concept

Development by the Navy of a CPGS option. These additions were intended to support the

program following testing complications in prior years. The House bill also contained a sense of

the Congress statement noting that “the United States must continue to develop the conventional

prompt global strike capability to strike high-value, time-sensitive, and defended targets from

ranges outside of current conventional technology while addressing and preventing any risk of

ambiguity.” It mandated that the Secretary of Defense submit a report by September 30, 2020, on

the outcome of the military requirements process and Milestone A decision for at least one

conventional prompt global strike weapons system.

The Senate, in its version of the NDAA (S. 1376), authorized $88.8 million for this program area.

In the report accompanying its bill (S.Rept. 114-49), the Senate Armed Services Committee noted

that this funding was intended to support DOD’s efforts to examine sea-based and ground-based

concepts and to support the flight experiment scheduled for March 2017. The Senate bill also

mandated that the Secretary of Defense make a Milestone A decision for the Conventional Prompt

Global Strike Weapons System no later than September 30, 2020, or eight months after the

successful completion of a second intermediate range flight test.

The conference report on H.R. 1735 adopts the Senate funding level, authorizing $88.8 million

for Prompt Global Strike Capability Development, with an added $5 million allocated to Concept

Development by the Navy and Concept Development by the Army. The report also adopts the

House language with respect to requesting a report by September 30, 2020, on the outcome of the

military requirements process and Milestone A decision for at least one conventional prompt

global strike weapons system.

FY2017

The DOD budget request for FY2017 included $181.3 million for Prompt Global Strike

Capability Development. Within this total, DOD allocated $174 million to the AHW—Alternate

Re-Entry System/Warhead Engineering—line. The request also included $2 million for

Hypersonic Glide Experiment and Concepts Demonstration Support, an activity that “supports

both ground and flight tests” and provides data needed to support a potential acquisition program.

The budget also includes $3.3 million for CPGS studies and $2 million for test range

development. This request, along with the plans to move forward with the testing program for the

AHW, further indicates that DOD is moving toward the development and deployment of a system

using the AHW glider and an intermediate-range booster, possibly deployed at sea.

Congress approved the DOD request of $181.3 million for Prompt Global Strike Capability

Development in the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328). It

also mandated, in Section 1688, that the Secretary of Defense make a Milestone A decision for

the program by September 30, 2020, or no later than eight months after the successful completion

of the second intermediate-range flight test. The legislation also limits the funds available for the

program to 75% of the authorized amount until Pentagon officials submit a report to Congress on

whether there are warfighter requirements for a “limited operational conventional prompt strike

capability” and whether the Pentagon’s plan and schedule for the CPGS program supports those



requirements. These provisions reflect congressional concerns about the pace and direction of the

CPGS program.

FY2018

The DOD budget request for FY2018 included $201.75 million for Prompt Global Strike

Capability Development. Within this total, DOD allocated $197.4 million to the AHW—Alternate

Re-Entry System/Warhead Engineering—line. The request also includes $1 million for

Hypersonic Glide Experiment and Concepts Demonstration Support, an activity that “supports

both ground and flight tests” and provides data needed to support a potential acquisition program.

The budget also included $3.3 million for CPGS studies. This request, along with the plans to

move forward with the testing program for the AHW, further indicates that DOD is moving

toward the development and deployment of a system using the AHW glider and an intermediate-

range booster, possibly deployed at sea.

Congress approved the Administration’s request for $201.75 million for Prompt Global Strike

Capability Development in the FY2018 National Defense Authorization Act (P.L. 115-91). It also

directed that the Secretary of Defense “plan to reach early operational capability for the

conventional prompt strike weapon system by September 30, 2022.” The legislation also

mandates that the Chairman of the Joint Chiefs of Staff submit a report to Congress that outlines

“the estimated period for the delivery of a medium-range early operational capability, the required

level of resources necessary to field a medium-range conventional prompt global strike weapon

within the United States (including the territories and possessions of the United States), or a

similar sea-based system, and a detailed plan consistent with the urgency of the associated

capability gap across multiple platforms.” The report should also provide a plan to address any

“potential risks of ambiguity from the launch or employment of such a capability.”

FY2019

The DOD budget request for FY2019 includes $278 million for the CPS program. This includes

$263 million in defense-wide research and development account and $15 million in Navy

research and development accounts. Within the defense-wide account, DOD has allocated the full

$263 million to the Alternate Re-Entry System/Warhead Engineering line. Moreover, as noted

above, the defense-wide research and development account contains no funding for the program

after FY2019, as the program is transitioning to the Navy’s research and development accounts in

FY2020.

The budget documents indicate that, in FY2019, the program will focus manufacturing and

testing the booster and hypersonic glide body that will be used in the second Flight Experiment

test and begin manufacturing and testing of the hypersonic glide body that will be used in the

third test. It will also, among other tasks, “continue studies for future system development to

examine cost, lethality, aerodynamic and thermal characteristics” and “conduct trade studies to

evaluate system alternatives, affordability, and end-to-end system concepts.”



Issues for Congress

Assessing the Rationale for CPGS

Reducing Reliance on Nuclear Weapons

When the Bush Administration first began to consider the deployment of long-range ballistic

missiles with conventional warheads, some analysts argued that, with improvements in accuracy,

conventional warheads could substitute for nuclear warheads in attacking some sites now targeted

by nuclear weapons. This type of “substitution” would have allowed the United States to reduce

its reliance on nuclear weapons and to reduce the number of nuclear weapons in its deployed

forces. Critics of this rationale, however, noted that conventional weapons could not really

substitute for nuclear weapons in U.S. deterrence strategy. Even if they had the accuracy and

explosive power needed to destroy some types of targets, they could not threaten the scale of

destruction and would not have the psychological effects of nuclear weapons. Most experts agree

that these characteristics are necessary for the weapons to deter conflicts with other nuclear-

armed nations.

As a result, most of the supporters of the prompt strike mission view these weapons as a “niche”

capability that would expand U.S. conventional options and reduce the likelihood that the

President might need to use a nuclear weapon in the absence of a conventional alternative. The

United States might only need a very small number of these weapons, for use against critical,

high-value targets or as the “leading edge” of a broader military campaign. Moreover, the United

States would plan for their use independent of its nuclear deterrent. The programs’ advocates note

that, in the absence of such a capability, in a circumstance when the United States believed it

needed to strike promptly at long ranges at the beginning of a conflict, the President might have

no choice other than to use a missile armed with a nuclear warhead. The CPGS capability would

provide that choice. In the 2010 Nuclear Posture Review, the Obama Administration extended

this logic to regional deterrence and the assurance of U.S. allies. If the United States had a wider

range of credible conventional weapons that it could turn to when defending its allies and forces

overseas, there could be fewer circumstances in which the United States might feel compelled to

resort to nuclear weapons for regional deterrence. This would not only reduce the role of nuclear

weapons in regional deterrence, it might also increase the credibility of the U.S. deterrent.

Some analysts have questioned, however, whether the President needs more options or flexibility

when responding to threats to U.S. or allied security. The President has never, in the past, been

faced with the choice of using a nuclear weapon or no weapon at all. The President has always

had a wide range of conventional options, even if the United States had to wait hours or days for

the weapons to arrive on target.

Many analysts have also argued that the deployment of CPGS might upset strategic stability and

increase the likelihood of nuclear war. Although the U.S. President might choose to initiate a

conflict or respond to a threat with a conventional attack, it is not clear that the adversary would

know that the incoming weapons carried conventional warheads. Moreover, the United States

would not be able to control the adversary’s reaction or the escalation of the conflict, particularly

if the adversary possessed nuclear weapons. Hence, by making the start of the war “easier” the

deployment of conventional warheads on ballistic missiles might, in this view, actually make the

eventual use of nuclear weapons more likely.



Russian officials have expressed a number of concerns about U.S. conventional prompt global

strike capabilities and their implications for strategic stability.98

They have argued that these

weapons, even if armed with conventional warheads, could threaten critical targets in Russia and

even threaten Russia’s strategic nuclear forces if the United States deployed large numbers of

missiles armed with highly accurate reentry vehicles. This might provide the United States with

the capability to undermine Russia’s nuclear deterrent, without resorting to the first use of nuclear

weapons, and might actually increase the likelihood of a U.S. attack against Russia. Moreover,

even if Russia were not the target of an attack with these missiles, it might not know whether the

missile carried a nuclear warhead or a conventional warhead, or whether it was headed towards a

target in Russia. Finally, some Russians have argued that the United States might replace the

conventional warheads with nuclear warheads to exceed the limits in a treaty.99

PGS

The PGS mission’s requirements are based on the assumption that a future conflict would take

place far from existing U.S. bases overseas, and possibly far from ocean areas where the United

States has deployed most of its sea-based forces. They also assume that a future conflict could

develop quickly, allowing too little time for the United States to move its forces into the region,

either by acquiring basing rights on land or by moving sea-based forces closer to the theater of

conflict. Further, the concern about hidden or relocatable targets reflects an assumption that

targets could appear with little notice and remain vulnerable for a short period of time, factors

that place a premium on the ability to launch quickly and arrive on target quickly. The

requirements also assume that U.S. forces are likely to face an “anti-access” threat, or air defense

capabilities that would impede operations by U.S. aircraft.

Many of these characteristics were present in Afghanistan in 2001, when the United States

attacked al Qaeda training camps and the Taliban government after the September 11 terrorist

attacks. The attacks on the United States came without warning, and, although the United States

took several weeks to plan its response and acquire the needed intelligence information on target

areas, speed was of the essence if the United States hoped to trap and destroy leaders at the

training camps in Afghanistan. The United States had no military bases in the region, and had to

take the time to acquire basing rights in nearby nations and to move U.S. naval forces into the

region. Further, the mountainous terrain offered the enemy areas where their leadership could

hide and hope to evade attack.

These characteristics, with the premium they place on prompt, long-range attacks, support the

view that the United States should deploy new boost-glide capabilities to meet the requirements

of the PGS mission. In this view, other weapons systems cannot address all the characteristics at

the same time; bombers may be too slow to arrive and too vulnerable to air defense systems, sea-

based or air-launched cruise missiles may also be too slow to arrive and of too short a range to

reach remote targets, and sea-based systems, with the exception of long-range ballistic missiles,

may also be too far away to reach high priority targets promptly at the sudden start of a conflict.

However, the presence of many of these characteristics in one recent conflict does not necessarily

mean that they will all be present in most, or even many, future conflicts. While each is certainly

98 Elaine M. Grossman, “Russian Experts Question Role of Conventional “Prompt Global Strike” Weapons,” Global

Security Newswire, April 7, 2009. 99 For a detailed discussion of stability concerns associated with CPGS, and a review of Russian and Chinese objections

to the program, see James M. Acton, Silver Bullet? Asking the Right Questions About Conventional Prompt Global

Strike (Washington, DC: Carneige Endowment for International Peace, 2013), pp. 111-126.



possible, taken together, these characteristics describe a worst-case scenario that may occur

rarely, or not at all, in its entirety. This observation highlights several questions that Congress

could consider when reviewing the rationale for the PGS mission. How likely is it that the United

States would face a sudden, unanticipated conflict, with no time to build up its forces in the

region and with the requirement to strike some targets within hours of the start of the conflict?

Would a delay of several hours or even days undermine the value of attacking these targets at the

start of a conflict? Could other weapons systems provide the United States with the ability to

“loiter” near the theater of operations, allowing a prompt attack during the conflict if hidden or

concealed targets are revealed?100

A comparison of the likelihood of those scenarios that may

provide the most stressing environments with the likelihood of less stressful scenarios may lead to

the conclusion that other weapons systems can respond to many of these requirements in most

circumstances.

The Potential for Misunderstanding a CPGS Missile Launch

Some Members of Congress and many analysts outside government have focused much of their

criticism of the PGS concept on the potential that other nations might detect the launch of a U.S.

CPGS missile and conclude, mistakenly, that the United States had launched an attack with

nuclear-armed missiles. Specifically, some have argued that, if the United States were to launch

these missiles during a conflict, nations with minimal satellite capabilities and launch notification

systems (such as China) or degraded launch notification systems (such as Russia) could conclude

that they were under attack with nuclear missiles.101

Further, because many possible targets lie

south of Russia and China, and the United States has historically planned to launch its ballistic

missiles over the North Pole, a conventionally armed long-range ballistic missile might fly over

these two nations to strike its targets. For many minutes during their flight patterns, these missiles

might appear to be headed towards targets in these nations. The potential for misunderstanding is

compounded by the short time of flight of these missiles, giving these nations little time to

evaluate the event, assess the threat, and respond with their own forces. Under such

circumstances, critics claim that these nations may conclude they have no other option than to

respond with their own nuclear weapons.

As was noted above, Congress raised concerns about the potential for misunderstanding in several

of its annual debates over the authorization and appropriations of funds for the CPGS mission.

These concerns grew as the Department of Defense planned to move ahead with the conventional

Trident modification (CTM). In response to these concerns, in the FY2007 Defense

Appropriations Act (P.L. 109-289), Congress provided $5 million for the National Academy of

Sciences to analyze the mission requirement and recommend alternatives.

The National Academies published the report—U.S. Conventional Prompt Global Strike: Issues

for 2008 and Beyond—in August 2008. This report recognized concerns about the potential for

misunderstanding, but concluded that these concerns should not eliminate pursuit of the program.

100 Barry Watts, an analyst expert in this subject has stated that, “for those rare occasions when it really is imperative to

be able to strike anywhere on the globe from the United States as quickly as possible, a long-range ballistic missile

solution is the most sensible near-term option in light of cost and technological risk.” But he has also asserted that it

may be “far more important to be able to dwell or loiter to await information and take advantage of opportunities” to

attack hidden or mobile targets during a conflict. Watts, Barry D. Long-Range Strike: Imperatives, Urgency and

Options, Center for Strategic and Budgetary Assessments, April 2005. 101 For a description of ongoing problems with Russia’s early warning system for ballistic missile attack, see Mosher,

David E. et al., Beyond the Nuclear Shadow: A Phased Approach for Improving Nuclear Safety and U.S.-Russian

Relations, RAND Corporation, 2003. p. 5.



The study noted that the United States and Russia had monitored and tracked the launches of

hundreds of ballistic missiles over the years, and they had demonstrated the capability to “acquire

sufficient data to determine their trajectory and hence … their target.”102

At the same time, the

study noted that the risk of misunderstanding could increase if the United States used boost-glide

technologies for the CPGS mission, because a nation’s ability to predict the target of such a

system would be undermined by the fact that these systems could maneuver and change their

direction after launch. Moreover, the study noted that the use of new, conventional-only launchers

or delivery vehicles would not necessarily mitigate the risks because “there is simply no ‘bright

line’ between nuclear and conventional systems when relatively long-range platforms are being

considered.”103

Mitigating the Risks

The National Academies study noted that concerns about the possible misinterpretation of a

launch were, however, limited at this time to Russia, because no other nuclear weapons state has

the ability to detect and track the launch of U.S. ballistic missiles.104

As a result, the United States

might be able to mitigate the risks of misunderstanding by altering the deployment and operating

patterns of systems armed with conventional warheads, and by cooperating with Russia to

demonstrate that these systems do not carry nuclear warheads.

For example, the Air Force indicated during its early studies that it could deploy missiles armed

with conventional warheads at bases, such as Vandenberg Air Force Base on the California coast,

that did not house missiles armed with nuclear weapons. According to the Air Force, “the new

coastal basing sites would have no nuclear capability or association,”105

as they would lack the

facilities and equipment needed to handle or store nuclear weapons. The United States could then

declare, to Russia or other nations, that these systems were equipped with conventional warheads.

This declaration would further demonstrate that the missiles at the two coastal bases were

different from nuclear ICBMs, even though it would not preclude the possible covert deployment

of nuclear warheads on the missiles.106

Further, their deployment with a hypersonic reentry body,

rather than a standard post-boost vehicle and warhead present on a nuclear-armed missile, would

reinforce this designation.107

The United States and Russia could also institute a number of cooperative measures to add

confidence to the U.S. declaration that the missiles deployed at coastal bases would carry

conventional warheads. These measures could include military-to-military contacts, high level

political consultations, and ongoing discussions to keep Russia informed about U.S. plans for

these missiles and to make them aware of the observable differences between conventional and

nuclear ballistic missiles.108

The United States could also invite other nations to observe test

102 National Research Council of the National Academies, U.S. Conventional Prompt Global Strike: Issues for 2008

and Beyond, Washington, DC, August 2008, p. 72. 103 Ibid., p. 72. 104 Ibid., p. 75. 105 Report to Congress on the “Concept of Operations” for the Common Aero Vehicle. Submitted in response to

Congressional Reporting Requirements, by Peter B. Teets, Under Secretary of the Air Force. February 24, 2004. p. 4. 106 The United States uses a similar formula with its B-1 bombers. Although they were originally equipped to carry

nuclear weapons, they have been deployed at bases that do not house nuclear weapons and redesignated as

conventional bombers. Hence, their weapons delivery status is determined by basing and declaration, rather than by

their original nuclear capabilities. 107 Air Force Space Command, Common Aero Vehicle White Paper, p. 8. 108 Ibid., p. 7.



launches of these missiles or to participate in exercises that include simulations with these

missiles. This might allow nations such as Russia to become familiar with the operational

procedures associated with the CPGS missiles and to distinguish between these procedures and

those associated with nuclear-armed missiles. Further, the United States could allow Russia to

conduct short-notice inspections at these bases to confirm the absence of nuclear weapons either

on the missiles or in the storage facilities.109

Over time, these measures would not only provide

information about the missiles and their missions, but might also build confidence and

understanding between the parties. The increased level of cooperation, and possibly decreased

level of suspicion, might then reduce the likelihood of misinterpretation if the United States were

to launch ballistic missiles with conventional warheads.

The United States could also provide Russia with prior notification of planned launches of

ballistic missiles with conventional warheads, or the two nations could set up a dedicated “hot

line” for use after a launch. That way, the United States could inform Russia of the launch and

assure it that the missile did not carry a nuclear warhead and was not headed for targets in Russia.

In addition, as has been discussed on many occasions over the years, the United States and Russia

could share early-warning data at a joint facility so that Russia would have the information it

needed to distinguish between the launch of a nuclear-armed ballistic missile from a northern

base and the launch of a conventional-armed ballistic missile from a coastal base.

The Air Force also indicated that the CSM, which would use a conventional booster and a

hypersonic payload delivery vehicle, would not follow the same trajectory as a nuclear-armed

ballistic missile. Specifically, the Air Force plans to launch the CSM on a “depressed trajectory”

that would achieve an altitude of only 500,000 feet. As a result, its flight would not resemble the

trajectories that would be followed by nuclear-armed ballistic missiles on course for targets in

Russia or China.110

DOD has indicated that the same would be true of a submarine-launched, intermediate-range

boost-glide system. It would follow a shaped or depressed trajectory, and would not resemble the

launch characteristics or trajectory of a nuclear-armed ballistic missile. Moreover, if the missile

used a new booster, rather than one that had been deployed as a part of the U.S. nuclear force, the

difference would likely be evident to Russia’s early warning systems.

Remaining Concerns

Taken together, these three types of measures might help reduce the risks of misunderstandings.

But the accumulation of information during peacetime and frequent communications during

crises may not be sufficient to address problems that could come up in an atmosphere of

confusion and incomplete information during a conflict. Specifically, the argument in favor of

using long-range ballistic missiles for the PGS mission assumes that the United States might have

little warning before the start of a conflict and might need to launch its missiles promptly at that

time. This scenario would allow little time for the United States to consult with, or even inform,

other nations about its intentions. If other nations are caught by surprise and fear they might be

under nuclear attack, they might also decide to respond promptly, before the United States had the

opportunity to convince them that the missiles carried conventional warheads.

109 Report to Congress on the “Concept of Operations” for the Common Aero Vehicle, Submitted in response to

Congressional Reporting Requirements, by Peter B. Teets, Under Secretary of the Air Force, February 24, 2004, p. 4. 110 Air Force Space Command, Common Aero Vehicle White Paper, p. 11.



Even though routine data exchanges and on-site inspections may provide confidence in the

absence of nuclear warheads on the missiles on a day-to-day basis in peacetime, they cannot

provide assurances that the warheads could not be changed in a relatively short period of time or

that the warheads were not actually changed in the days or weeks since the last inspection. In

addition, changing the basing patterns or launch patterns of missiles to draw a sharper distinction

between conventional and nuclear-armed missiles assumes both that other nations can observe the

differences and that they believe the different appearances indicate different warheads. Finally,

these measures would do nothing to alleviate concerns among nations that did not participate in

the cooperative programs.

As a result, while the measures described above can reduce the possibility of misunderstandings,

they probably cannot eliminate them. Moreover, they cannot address concerns, often expressed by

officials in Russia and China, that the United States might use these weapons, along with other

conventional strike systems and missile defenses, to acquire a the ability to attack strategic or

nuclear targets in these nations without resorting to the use of U.S. nuclear weapons.

Reviewing the Alternatives

As the preceding discussion indicates, the United States has considered a number of alternatives

for weapons systems that could contribute to the PGS mission. For a time, the Air Force CSM,

armed with a payload delivery vehicle derived from either the DARPA/Air Force HTV-2 vehicle

or the Army AHW vehicle, appeared to be the main contender for this mission at the present time.

However, because the HTV-2 has not had a successful test flight and the AHW, which has tested

successfully, may be better suited to an intermediate-range system, a submarine-launched missile

armed with the AHW is now be the leading contender for the conventional prompt strike mission.

But these are not the only options for precision, conventional strike weapons, particularly if a

system with shorter range or longer delivery times can meet some of the requirements. As a

result, while reviewing Administration requests for funding for the conventional prompt strike

mission, Congress could consider a range of alternative weapons systems.

Land-Based Ballistic Missiles

Long-range land-based ballistic missiles armed with conventional warheads, even if they relied

on standard ballistic missile reentry bodies instead of boost-glide technologies, would likely

possess many of the operational strengths associated with nuclear-armed ballistic missiles. They

might have extremely high rates of readiness and reliability, allowing military planners to expect

more than 90% of the missiles to be available for use at any given time; they could likely respond

promptly after a decision to launch; and, when armed with a hypersonic payload delivery vehicle,

they would likely have a high degree of accuracy allowing for attacks across a wide range of

targets. Consequently, these systems would “free the U.S. military from reliance on forward

basing and enable it to react promptly and decisively to destabilizing or threatening actions by

hostile countries and terrorist organizations.”111

These weapons would probably address all the

potential circumstances cited in requirements for the PGS mission.

However, as is noted above, many analysts have expressed concerns about the possibility that the

launch of these missiles could generate misunderstandings within other nuclear-armed nations

and undermine strategic stability because they would follow the same ballistic missile trajectories

111 DARPA, “FALCON (Force Application and Launch from CONUS Technology Demonstration Program,” Fact

Sheet, November 2003.



as U.S. nuclear-armed missiles. Even if the United States based and operated these missiles

differently from nuclear-armed missiles and cooperated with other nations to demonstrate that

these missiles did not carry nuclear warheads, other nations, such as Russia or China, could still

question whether the missiles launched during a conflict carried conventional warheads or

whether the United States had converted them back to carry nuclear warheads.

Submarine-Launched Ballistic Missiles

Submarine-launched ballistic missiles armed with conventional warheads could have many of the

same benefits as land-based missiles. As nuclear delivery vehicles, they have been deployed with

the command and control systems needed to allow for prompt decision making and prompt

launch during a crisis. They have the range to reach targets around the world and they could have

the accuracy, particularly if armed with hypersonic payload delivery vehicles, to attack a wide

range of targets on short notice.

SLBMs armed with conventional warheads, however, would also raise many of the same

questions about misunderstandings as land-based ballistic missiles, particularly if these warheads

were deployed on the same submarines that currently carry nuclear warheads. The Navy could not

employ many of the techniques identified by the Air Force to convince potential adversaries that

the missiles carried conventional warheads. Even if the United States did deploy SLBMs with

conventional warheads on submarines that did not carry nuclear warheads, it would be extremely

difficult to demonstrate these differences and assure other nations of the segregated deployments

in a submarine that is intended to be hidden and invulnerable when at sea. Further, according to

some reports, Russia’s ability to monitor U.S. SLBM launches is even more degraded than its

ability to monitor ICBM launches, so it might conclude that it is under nuclear attack if it

observed an SLBM launch from a U.S. ballistic missile submarine.

On the other hand, because the submarines are mobile and the missiles are long-range, the United

States could alter the patrol areas for Trident submarines so that, if they were to launch their

conventional missiles, they could use trajectories that did not require them to fly over these

nations on their way to their intended targets. Alternatively, the submarines could move prior to

launching their missiles, to avoid overflight of Russia or China, but this presumes that the United

States had the time to move its submarines to these new launch points prior to the start of the

conflict, a possibility that is inconsistent with the PGS mission’s assumption that the United

States could need to launch its missiles promptly at the start of an unexpected conflict.

Long-Range Bombers

U.S. bombers—B-52s, B-2s, and B-1s—have the range and payload needed to deliver weapons to

targets across the globe. But they may not be suited to the PGS mission because they could take

hours or days to reach targets in remote areas, and they would require tanker support to refuel

during their missions. The long flight time could contribute to crew fatigue, and air defenses

could deny the bombers access to some critical target areas. The long flight time could also

provide adversaries with warning of the impending attack. Conventional cruise missiles delivered

by B-52 bombers would allow the aircraft to stay out of the range of some air-defense systems,

but they could still take too long to reach their targets to meet the objectives of the PGS mission.

On the other hand, the long flight duration could give the United States time to review and

resolve the situation without resorting to military attacks. Moreover, because accurate and timely

intelligence reports are critical to the success of long-range strike missions, the United States

could use the time during the bombers’ flights to acquire and update information on the target of

the attack.



Tomahawk Cruise Missiles

At the present time, the Navy has the capability to attack targets at ranges of around 1,500

nautical miles with sea-based cruise missiles. These Tomahawk missiles have been employed

often in the conflicts in the past 20 years, providing the United States with the ability to reach

targets without risking aircraft or their crews. The Navy has modified four of its Trident ballistic

missile submarines so that they can carry cruise missiles. These submarines are equipped to carry

up to 7 Tomahawk missiles each in up to 22 (out of 24) of their Trident launch tubes, for a total of

154 cruise missiles per submarine. But these missiles may be limited in their ability to contribute

to the PGS mission. With a maximum speed of about 550 miles per hour and a range of 1,500

nautical miles, they can take two to three hours to reach their targets. Moreover, their reach is

limited, even if the ships or submarines carrying the missiles are deployed in the region of the

conflict. Consequently, the Navy has also explored alternatives that would allow it to reach its

potential targets more quickly.

Hypersonic Cruise Missiles

Since the mid-1990s, the Navy has explored several options for the development and deployment

of an attack missile that could travel at speeds of Mach 3 to Mach 5.112

These hypersonic missiles

would allow the Navy to attack targets within 15 minutes from ships or submarines based within

500 to 600 nautical miles of their targets. Hence, they would provide the capability for prompt

strikes within the theater of operations, but they would not have the range sought for the PGS

mission. The United States would either need to keep its vessels on station near potential areas of

conflict, which it already does in certain areas, or it would need days or weeks to move its ships

or submarines into place.

Scramjet Technologies

The Air Force, in collaboration with DARPA, NASA, and the Navy, is developing scramjet—

supersonic combustion ramjet—technologies that may contribute to the long-range strike mission

in the future. In this type of vehicle, the engine gets the oxygen it needs for combustion from the

atmosphere passing through the vehicle, instead of from a tank onboard. This eliminates the need

for heavy reservoir oxygen tanks, and makes the vehicle far smaller, lighter, and faster than a

conventional rocket. According to NASA, a scramjet could, theoretically, travel at 15 times the

speed of sound.113

The scramjet would destroy targets by crashing into them at hypersonic speeds.

However, the Air Force may also use the technology to create a payload delivery vehicle that

might carry conventional munitions and be launched on a long-range missile.114

The Air Force has designed an experimental scramjet, the X-51 WaveRider, that it can release

from an Air Force bomber. It conducted a flight test of this vehicle on May 26, 2010. In this test,

the vehicle was released at an altitude of 50,000 feet, from under the wing of a B-52 bomber.115

An Army tactical missile solid rocket booster accelerated the X-51 to a speed of approximately

112 For a summary of these programs see Statement of Ronald O’Rourke, Specialist in National Defense, Congressional

Research Service, before the House Armed Services Committee, Subcommittee on Projection Forces, Hearing on

Long-Range Strike Options, March 3, 2004. pp. 10-11. 113 http://www.nasa.gov/missions/research/f_scramjets.html. 114 Boeing, “Boeing X-51A WaveRider Breaks Record in 1st Flight,” Information Sheet,

http://www.boeing.mediaroom.com, May 26, 2010. 115 Boeing, “Boeing, Air Force Research Lab, Pratt & Whitney Rocketdyne to Conduct X-51A WaveRider Flight Test

on May 25,” Information Sheet, http://www.boeing.mediaroom.com, May 20, 2010.



Mach 4.8, the speed required for the engine to ignite. The Air Force had intended for the scramjet

to fly 300 seconds and reach speeds of 4,500 miles per hour, or six times the speed of sound.116

However, the vehicle did not reach either of those thresholds before it began to slow down.

Reports indicated that the engine was flying normally when the vehicle started having control

problems and was eventually terminated.117

The Air Force conducted three additional tests of the X-51A WaveRider. In the 2011 test, a

mechanical problem caused it to end its operations earlier than planned. In the 2012 test, the

system lost control due to a “faulty control fin” seconds after it the rocket booster ignited.

However, in a fourth and final test of the X-51A in May 2013, the WaveRider reached a speed of

Mach 5.1 and an altitude of 80,000 feet during its 300-second test flight.

DARPA and the Air Force continue to pursue the development of scramjet technologies and air-

breathing hypersonic capabilities. Air Force research funding has increased from a level of around

$80 million in FY2012 to a request for $292 million in FY2018 and $258 million in FY2019.118

The research is focusing on the development of hypersonic cruise missiles that could be launched

from fighters and bombers, including a program known as the hypersonic air-breathing weapon

concept, and one known as tactical boost glide program.

This technology remains in its early stages, and could not contribute to the PGS mission for

several years. However, because these vehicles would not leave the atmosphere or fly on a

ballistic missile trajectory, they may address the nuclear ambiguity issues raised by long-range

ballistic missiles in the CPGS program.

Forward-Based Global Strike (FBGS)

The United States could also deploy intermediate or long-range, land-based ballistic missiles at

bases outside the continental United States. For example, they might be deployed in Guam, Diego

Garcia, or Alaska. This system could use a two-stage rocket motor, to distinguish them from

current nuclear-armed ICBMs, and could also, like the SLIRBM, carry either a guided warheads

the AWH hypersonic glider. In addition, because it would be launched from outside the

continental United States, its trajectory would not resemble that of a land-based ICBM. Hence,

some analysts argue that it would solve many of the questions about the potential for

misunderstandings and misperceptions. If the missiles had a range of less than 5,500 kilometers,

they would be inconsistent with the limits in the 1987 Intermediate-Range Nuclear Forces Treaty.

However, the United States has recently charged that Russia is in violation of the INF Treaty,

leading some to conclude that this agreement should no longer constrain U.S. plans for

intermediate-range systems.119

Arms Control Issues

In April 2010, the United States and Russia signed a new strategic arms reduction treaty, known

as New START.120

During the negotiations on New START, Russia voiced concerns about U.S.

116 Ibid. 117 “Early Waverider Findings,” Aviation Week and Space Technology, June 7, 2010. 118 Vivienne Machi, “Future Weapons: Rivals Push Pentagon to Boost Funding for Hypersonics Research,” National

Defense, June 26, 2017. 119 For information on the current dispute over the INF Treaty, see CRS Report R43832, Russian Compliance with the

Intermediate Range Nuclear Forces (INF) Treaty: Background and Issues for Congress, by Amy F. Woolf. 120 For details on the limits and restrictions in this Treaty see CRS Report R41219, The New START Treaty: Central

(continued...)



plans to deploy conventional warheads on ballistic missiles that now carry nuclear warheads. As

was noted above, Russia believes these weapons would undermine strategic stability and increase

the risk of nuclear war. The Obama Administration responded to Russia’s concerns by noting the

United States does not plan to target its PGS systems against Russia and that the United States

would not deploy enough of these weapons to threaten Russia’s strategic deterrent. Nevertheless,

the preamble to the new treaty states that the parties are “mindful of the impact of conventionally

armed ICBMs and SLBMs on strategic stability.” However, according to the Obama

Administration, neither this statement nor any other provisions in the treaty will “in any way limit

or constrain research, development, testing, and evaluation (RDT&E) of any strategic concepts or

systems, including prompt global strike capabilities.”121

During the negotiations on New START, Russia initially sought to ban the deployment of

conventional warheads on strategic ballistic missiles. The United States rejected this proposal

because it would have interfered with ongoing U.S. plans and programs for the CPGS mission. As

Rose Gottemoeller, the Assistant Secretary of State for Arms Control, Verification and

Compliance, noted when she testified before the Senate Foreign Relations Committee, “We were

firm during the negotiations that the treaty must allow for strategic missiles [of] conventional

configuration.”122

At the same time, however, the United States agreed that ballistic missiles

armed with conventional warheads that were otherwise consistent with the treaty’s definition of

strategic ballistic missiles would count against the treaty’s limits on deployed delivery vehicles.

The warheads deployed on these missiles would similarly count against the treaty’s limits on

deployed warheads.123

Hence, under New START, U.S. land-based ballistic missiles armed with conventional warheads

would count under the limits in New START if, according to paragraph 6 of Part One of the

Treaty Protocol, the missile “has a ballistic trajectory over most of its flight path” and a range

greater than 5,500 kilometers. Submarine-launched ballistic missiles would meet this criteria if

they traveled on a ballistic trajectory for most of their flight path and had a range greater than 600

kilometers. Administration officials have explained that the United States accepted this provision

because it would be nearly impossible to distinguish between a missile armed with nuclear

warheads and one armed with conventional warheads, and, therefore, extremely difficult to verify

compliance with the treaty limits if the missiles with conventional warheads did not count.

Moreover, the Administration insisted that, although the United States might have to reduce its

number of nuclear warheads if it deployed conventional warheads on ballistic missiles that met

this definition, the treaty’s limits were high enough to “accommodate the level of CPGS

deployments that is foreseeable over the lifetime of the treaty.” In response to a question posed by

the Senate Foreign Relations Committee, Secretary of Defense Gates stated that

as envisaged by our military planners, the number of such conventionally armed delivery

vehicles and the warheads they carry would be very small when measured against the

(...continued)

Limits and Key Provisions, by Amy F. Woolf. 121 U.S. Congress, Senate Committee on Foreign Relations, Treaty With Russia on Measures for Further Reduction and

Limitation of Strategic Offensive Arms (the New START Treaty), 111th Cong., 2nd sess., October 1, 2010, Exec Rpt.

111-6, p. 56. See, also, U.S. State Department, Bureau of Verification, Compliance, and Implementation, Conventional

Prompt Global Strike, Fact Sheet, Washington, DC, April 8, 2010, http://www.state.gov/t/vci/rls/139913.htm. 122 U.S. Congress, Senate Committee on Foreign Relations, Treaty With Russia on Measures for Further Reduction and

Limitation of Strategic Offensive Arms (the New START Treaty), 111th Cong., 2nd sess., October 1, 2010, Exec Rpt.

111-6, pp. 51-52. 123 Ibid., p. 52.



overall levels of strategic delivery systems and strategic warheads. Should we decide to

deploy them, counting this small number of conventional strategic systems and their

warheads toward the treaty limits will not prevent the United States from maintaining a

robust nuclear deterrent.124

According to Administration officials, the New START Treaty, would, therefore, count the

warheads deployed on CPGS systems, like the Navy’s conventional Trident modification, that

delivered reentry vehicles along a ballistic missile trajectory. It would not, however, capture

warheads deployed on boost-glide systems, like the Air Force’s conventional strike missile, that

launched along a depressed trajectory and used a hypersonic glide vehicle to deliver weapons to

targets. In testimony before the Senate Foreign Relations Committee, Principal Deputy Under

Secretary of Defense for Policy James Miller stated that because boost-glide systems fly on a

non-ballistic trajectory, “we are confident that such non-nuclear systems,” which do not otherwise

meet the definitions for the New START Treaty, “would not be accountable as new kinds of

strategic offensive arms for the purposes of the treaty.”125

Under the definitions in New START, these types of systems would qualify as new kinds of

strategic offensive arms. Article V of the treaty indicates that, “when a Party believes that a new

kind of strategic offensive arm is emerging, that Party shall have the right to raise the question of

such a strategic offensive arm for consideration in the Bilateral Consultative Commission.” As a

result, Russia would have the opportunity to question the United States on whether the boost-

glide systems should count under the treaty. But the United States would not have to delay the

development, testing, and deployment of these systems while the discussions proceeded and it

would not have to defer their deployment if Russia did not agree with the U.S. conclusion that

these systems did not count under New START. In the article-by-article analysis submitted with

the New START Treaty, the State Department indicated that “the deploying Party would be

obligated to attempt to resolve the issue within the framework of the BCC [emphasis added].”

But, according to the State Department, “there is no requirement in the treaty for the deploying

Party to delay deployment of the new system pending such resolution.”126

Potential Threats from Hypersonic Strike

Section 1687 of the Defense Authorization Bill for Fiscal Year 2017 (P.L. 114-328) designates the

Director of the Missile Defense Agency as DOD’s executive agent for the development of a U.S.

capability “to counter hypersonic boost-glide vehicle capabilities and conventional prompt strike

capabilities that may be employed against” the United States, its allies, and its forces overseas. It

mandates that the director develop “architectures for a hypersonic defense capability” and

develop a program of record for this capability by September 30, 2017.

This provision reflects growing concerns in Congress and among some in the defense community

about the efforts by potential U.S. adversaries, including Russia and China, to develop hypersonic

boost-glide systems and, in some cases, hypersonic cruise missiles.127

The Strategic Forces

Subcommittee of the House Armed Committee addressed these programs in a hearing in late

124 Ibid., p. 54. 125 Ibid., p. 55. 126 U.S. Department of State, Article-by-Article Analysis of the New START Treaty Documents, Washington, DC, May

5, 2010, http://www.state.gov/t/avc/trty/141829.htm#text. 127 Bill Gertz, “Air Force: Hypersonic Missiles from China, Russia Pose Growing Danger to U.S.,” Washington Free

Beacon, November 30, 2016. See, also James Acton, “The Arms Race Goes Hypersonic,” Foreign Policy, January 30,

2014.



2015. Further, a study published by the National Academy of Sciences in late 2016 highlighted

the complexities that such programs create for U.S. defensive programs and the “gaps and seams”

that exist in U.S. efforts to address the threat. The summary to the study stated that high-speed

maneuvering weapons, such as hypersonic cruise missiles or boost-glide vehicles, “can combine

speed and maneuverability between the air and space regimes to produce significant new

offensive capability that could pose a complex defensive challenge.”128

Members of Congress and Pentagon officials have expressed growing concerns with Russian and

Chinese hypersonic programs, and have highlighted that the United States does not have the

capability to defend against these missiles.129

General Hyten has also noted that the Pentagon’s

FY2019 budget includes $42 million for the Air Force and the Missile Defense Agency to work

on a prototype for space-based sensors that could track hypersonic missiles after launch and assist

in the defense against them.130

Weighing the Benefits and Risks

The Bush Administration and the Obama Administration both supported the deployment of

systems that employ long-range booster rockets and hypersonic payload delivery systems to

fulfill the requirements of the prompt global strike mission. Both Administrations have argued

that these systems can provide the United States with the ability to attack anywhere in the world

on short notice, in support of regional or national security goals. They have both noted that, by

strengthening the U.S. ability to attack at long ranges with conventional weapons, these systems

could help reduce the number of circumstances when the United States might have to consider

using nuclear weapons to defend its interests. The Trump Administration continues to support the

development and deployment of these systems, although it has not linked them to effort to reduce

U.S. reliance on nuclear weapons.

Critics, however, have argued that these weapons might provide the United States with more

capability than it needs under most circumstances, while, at the same time, raising the possibility

that their use might be misinterpreted—either as the launch of nuclear weapons or as the use of

conventional weapons against nuclear targets. Moreover, as would be true for any weapon

seeking to achieve this mission, the ability to attack targets across the globe on short notice

depends on the U.S. ability to acquire precise information about the locations of potential targets

and to translate that information into useful targeting data. If it takes longer for the United States

to acquire and use that information than it would take for it to launch and deliver a ballistic

missile, or, as has often been the case, if such precise information is unavailable, then the United

States may not be able to benefit from the unique characteristics of long-range ballistic missiles.

Bombers would take longer to reach their targets, but this added time might provide the United

States with the opportunity to acquire the needed intelligence. A 2008 report by the Government

Accountability Office (GAO) identified this particular problem, noting that many of the ongoing

128 National Academy of Sciences, High-Speed Maneuvering Weapons: A Threat to America's Global Vigilance,

Reach, and Power, Unclassified Summary, Washington, D.C., November 2016, p. 4,

https://www.nap.edu/read/23667/chapter/1#ii. 129 Barbara Starr, “US general warns of hypersonic weapons threat from Russia and China,” CNN, March 27, 2017,

https://www.cnn.com/2018/03/27/politics/general-hyten-hypersonic-weapon-threat/index.html?sr=

twCNN032718general-hyten-hypersonic-weapon-threat0600PMVODtop. 130 Rebecca Kheel, “Russia, China eclipse US in hypersonic missiles, prompting fears,” The Hill, March 27, 2017,

http://thehill.com/policy/defense/380364-china-russia-eclipse-us-in-hypersonic-missiles-prompting-fears.



studies into global strike and prompt global strike have not addressed the need for critical

enabling capabilities along with the weapons systems that would be used in the attacks.131

In addition, long-range ballistic missiles using boost-glide technologies would have an advantage

over sea-based systems if the United States did not have naval forces near the conflict region, or

did not have time to move these forces to the area, or if the target area were out of range for the

sea-based systems. But the U.S. Navy deploys its force around the world and maintains

capabilities near likely areas of conflict. A few targets may be out of range for these weapons, but

bombers armed with cruise missiles might be able to reach them. Land-based long-range ballistic

missiles would only be needed in the rare circumstance where the United States had no warning,

needed a prompt attack, and had to reach too far inland for sea-based systems. But even in these

circumstances, the benefits of the use of long-range ballistic missiles might not outweigh the

risks.

During the Cold War, most analysts recognized that long-range land-based ballistic missiles could

prove destabilizing in a crisis, when nations might have incomplete information about the nature

of an attack and too little time to gather more information and plan an appropriate response.

Faced with these circumstances, a nation who was not an intended target, such as Russia, might

choose to respond quickly, rather than to wait for more information. The same could be true for

the adversaries who are the intended targets of U.S. conventional prompt strike weapons. If the

United States hoped to destroy a nation’s military forces or weapons of mass destruction at the

start of a conflict, before they could be used to degrade U.S. capabilities or attack U.S. forces, the

other nation might choose to use these weapons even more quickly during a crisis, before it lost

them to the U.S. attack.132

Some have argued that the possible crisis instabilities associated with long-range ballistic missiles

should not eliminate them from consideration for the conventional prompt strike mission because

the United States can work with Russia, China, and other nations to reduce the risks; also because

no other weapons, at least in the short term, provide the United States with the ability to attack

promptly anywhere on the globe at the start of an unexpected conflict. Yet the question of whether

the United States should accept the risks associated with the potential for misunderstandings and

crisis instabilities can be viewed with a broader perspective. How likely is the United States to

face the need to attack quickly at great distances at the start of an unexpected conflict? How much

would the United States lose if it had to wait a few hours or days to move its forces into the

region (or to await the intelligence reports and precise targeting data needed for an attack)?

If the risks of waiting for bombers or sea-based weapons to arrive in the theater are high, then

long-range ballistic missiles may be the preferred response, even with the risk that other nations

might misunderstand U.S. intentions. On the other hand, if the risks of waiting for other forces to

arrive in theater are deemed to be manageable, and the risks of potential misunderstandings and

crisis instabilities associated with the launch of long-range ballistic missiles are thought to be

high, then the United States can consider a broader range of alternative weapons systems to meet

the needs of the PGS mission.

131 U.S. Government Accountability Office, Military Transformation, “DOD Needs to Strengthen Implementation of its

Global Strike Concept and Provide a Comprehensive Investment Approach for acquiring Needed Capabilities.” GAO-

08-325. April 2008. p. 5. 132 James M. Acton, Silver Bullet? Asking the Right Questions About Prompt Global Strike (Washington, DC: Carnegie

Endowment for International Peace, 2013), pp. 120-129.



Author Contact Information

Amy F. Woolf

Specialist in Nuclear Weapons Policy

[email protected], 7-2379

Acknowledgments

Melisa Woolfolk contributed diligent research and valued assistance in the preparation of this report.